Miles |
|
| 0.0 | Thompson River Entrance, Rocky Mountain
National Lark. Just beyond the entrance the road to Bear Lake turns
abruptly left, crossing Thompson River to Camp Woods in Tuxedo Park.
Keep straight ahead on road to Moraine Park. The gravel and boulders on
the right belong to the moraine of a glacier older than the last or
Wisconsin stage of glaciation. This glacier flowed down the Thompson
Valley and spread its deposits beyond the limits of the later glacier
(see p. 19, point 2.4 miles). |
| 0.1 | Steep grade around the base of Eagle Cliff.
Dark schist with intrusions of white pegmatitic granite (granite
containing large crystals) is exposed in road cut on right. Note the
shining crystals of black mica in the schist which lie in parallel
planes and cause the rock to cleave readily in those planes. The granite
has been intruded in thin layers along the cleavage planes of the schist
and in places has broken across them. At bend in road is exposed a mass
of granite which has welled up into the schist and is disintegrating due
to the breaking down by weathering of the feldspar crystals which are
present in it. Just beyond, a lense of pink and white granite from 2 to
6 feet thick has been intruded between the planes of the schist and dips
to the east. Its color is due to the presence of both pink and white
feldspar crystals. |
| 0.3 | Crest of terminal moraine of the great glacier
which during the Wisconsin or last stage of the Ice Age covered Moraine
Park. |
| 0.5 | Road follows base of terminal moraine which is
banked against the foot of Eagle Cliff. Here the advance of the ice was
halted by the cliff, and the gravel and sand carried by the glacier were
deposited in a ridge as the ice melted. |
| 0.7 | Junction with road to Stead's Ranch. Keep
right. To the south rises the pine-covered south lateral moraine of the
former Thompson Glacier. Its height indicates the height of the glacial
ice which decreased toward the east as the ice melted in the warmth of
the lower altitude. At the end of the former glacier the lateral merges
with the terminal moraine.
To the north, beyond the groves of aspen, stretches
the pine-covered north lateral moraine, its western end banked against
the mountain at the mouth of the canyon down which the ice flowed. The
top of this moraine, like that of the south lateral, slopes to the east,
the inclined line of its crest being plainly visible against the
mountain side.
The flat valley of Moraine Park (fig. 12) was the
melting basin of the glacier and was occupied as the ice melted back by
a glacial lake. The waters of this lake, impounded by the terminal
moraine, were later drained away when the outlet cut through this
natural dam. The present stream swings in broad meanders across the flat
which was the lake bed, because it does not have enough fall to give
direction to its waters. Rising from the flat in the distance is a rock
island which the glacier was unable to destroy, although it ground down
the west side to a gentle slope.
|
Figure 12.Moraine Park from the
museum. The even-topped pine-covered ridge on the left is the south lateral
moraine, or deposit of boulders, gravel, and sand, left by the former
Thompson Glacier. Its height indicates the height of the glacial ice.
The flat is the bed of a former lake, impounded as the glacier melted,
by the terminal moraine which the glacier threw across the valley. Note
the U-shaped gorge, in distance on right, down which the glacier moved.
Photograph by Carroll H. Wegemann
|
Around the east side of the lake the road follows
what appears to be an old lake terrace or shore line formed by the waves
when the lake stood at its initial high stage before the lowering of its
outlet. As the outlet was deepened and the waters drained away, the lake
established a new and lower shore line leaving the old terrace dry, to
be cut away, in part, by the waves and stream erosion.
|
| 1.1 | Moraine Park Museum, on right, contains
exhibits illustrative of Indian life, pioneer history, wildlife, and
glacial geology. |
| 1.4 | Begin climb of north lateral moraine
(Wisconsin stage or last glacial advance) of Thompson Glacier. The open
air amphitheatre is on the south side of the road. |
| 1.9 | Road curve on crest of moraine. |
| 2.1 | North base of lateral moraine (Wisconsin
stage). |
| 2.3 | Cross Beaver Brook. |
| 2.4 | Road emerges from aspen grove in Beaver Park.
Ahead are scattered pine trees growing on a low gravel and boulder ridge
which is the north lateral moraine of an earlier glacier than that of
the Wisconsin stage, the moraine of which has just been crossed. The
older glacier was larger than its successor. It flowed down the Thompson
Valley and occupied Moraine Park, but all evidence of it has been
obliterated by the later glaciation except in Beaver Park and Tuxedo
Park, where its moraines lie outside the area covered by the later ice.
The gravel in these old moraines is very much weathered. In fact some of
the stones can be crumbled in the fingers. The gravel has obviously
been subjected to weathering for a period several times as long as that
to which the practically unweathered gravel in the moraines of the last
ice advance was subjected. The old lateral moraine can be traced for a
short distance down the valley until it merges with the old terminal
moraine which turns south and is banked against Eagle Cliff. The road
follows the south side of the old moraine to the west. |
| 2.7 | Curve to the right across the old moraine
which is so low at this point as to be scarcely recognizable. |
| 2.8 | Dirt road leads left to Upper Beaver Park. Keep
to the main road. |
| 3.1 | Sharp curve to left on shoulder of Deer
Mountain. From this point an excellent view can be had of the several
moraines just described. |
| 3.3 | Rock cut. A light-colored granitic dike
containing large crystals of shiny mica, which separate in thin sheets,
is well exposed on left and can be seen also on right. The dike
represents molten rock which was intruded into the older rock at great
depth and cooled so slowly that the large crystals had time to form
before the molten rock solidified. Erosion has lowered the surface and
exposed the granite. |
| 4.6 | Second rock cut is through rusty colored
granite which here stands in a ridge because it is harder than the rock
on either side. From this point one may view the even-crested north and
south moraines of the last Thompson Glacier. Longs Peak is the highest
flat-topped summit dominating the skyline on the south. |
DEER RIDGE JUNCTION TO FALL RIVER PASS VIA FALL RIVER
|
Miles |
|
| 5.3 | Deer Ridge Junction. The left road is the
usual route taken to Fall River Pass via Trail Ridge. The right road
leads to the same pass by way of Horseshoe Park and Fall River. It is a
narrow winding mountain road, but is safe for experienced mountain
drivers. Beyond Chasm Falls it is open only to cars going up. By taking
it one can make a circle trip, returning down Trail Ridge to Deer Ridge
Junction. For this circle trip over the Fall River Road keep right. If
you decide to take the Trail Ridge Road, keep left, and turn to page 29,
point 5.3 miles using the left-hand mileage column and reading the
descriptions of the various points in reverse order. In other words,
read up on the pages. |
| 5.9 | In the road cut on left large glacial boulders
are seen resting on poorly exposed bedrock which originally formed the
south side of the Fall River Valley. When the glacial ice moved down
this valley it deposited its lateral moraine against the bedrock and the
road cut has exposed the basal boulders. Some of these have been moved
to protect the bank against erosion, but their position still marks the
base of the moraine. Just beyond, the road crosses Hidden Valley Creek,
the origin of which will be described from Rainbow Curve (see p. 27,
point 9.3 miles) on the Trail Ridge Road. |
| 6.8 | Base of lateral moraine on south side of
Horseshoe Park. The flat valley, like that of Moraine Park, is the bed
of a glacial lake impounded by a terminal moraine which crosses the
valley 2 miles farther down. This stop is on an old lake terrace built
by the waves when the lake stood at one of its higher stages. |
| 6.9 | Edge of terrace, against which the waves broke
after the lake level had been lowered by the deepening of the outlet
through the terminal moraine. |
| 7.1 | Cross Fall River. Just ahead the road forks.
Take left road up valley, leaving Route 34. |
| 7.5 | Fall River Lodge. |
| 7.8 | Roaring River. The rapid fall of such side
streams is due to lowering of the Fall River valley by the last glacier.
This left the mouths of the side valleys, which contained smaller
glaciers or no glaciers at all, "hanging" so that their waters now reach
the main valley by a series of cascades. It is evident that the valley
of Fall River must have been lowered some 400 feet by the gouging of the
glacial ice. |
| 8.5 | Point of granite on right projects into
valley. Below this point the road follows the foot of the north lateral
moraine of the Fall River Glacier. In the narrow valley above, however,
there is no moraine because the ice was so confined and flowed under
such pressure between the granite walls that no gravel was dropped along
the base of the cliffs. Nevertheless, some morainal material was banked
high up on the valley sides. |
| 9.0 | Road to Endovalley Campground. Keep
right. |
| 9.4 | Chiquita Creek. Before the last glacier had
deepened the valley of Fall River and thrown its lateral moraines across
the mouths of its side streams, Chiquita Creek joined the main valley
without a fall like any normal stream. Now, due to the work of the
glaciers of the Ice Age, it cascades down to the main valley in a series
of falls. The rock is coarse reddish granite. |
| 9.6 | The granite ledge just above the road has been
smoothed and polished by the stones frozen in the base of the glacial
ice and ground across it by the glacier's flow. |
| 9.7 | Pot hole on right next to road. This circular
hole 2 or 3 feet in diameter was drilled by stones revolving in a
whirlpool in some side stream which probably flowed at this level
during, or just after, the last glaciation. Note that the main stream is
several hundred feet below. |
| 10.0 | First switch-back. |
| 10.2 | Glacial polish on ledge just above road
similar to that at 9.6 miles. |
| 10.4 | Chasm Falls. The beautiful waterfall is about
25 feet in height and is drilling, at its foot, a pot hole similar to
that at point 9.7 miles. From this the water drops about 5 feet into a
second hole, the half-round side of which may be seen in the cliff above
the water. About 20 feet downstream from the base of the main fall the
remains of a third pot hole are to be seen. It is evident that the
stream is literally drilling out its narrow gorge in the solid rock by
revolving loose boulders in its whirlpools. As the cataract recedes, the
upstream side of the last pot hole is cut away so that the half-round
hollows in the walls of the gorge are all that remain.
There is glacial polish on the rock ledge just above
the parking area.
|
| 10.7 | Here a perpendicular face of granite, some 20
feet long and 12 feet high, rises above the road. Its top is rounded and
polished by the gravel and sand frozen in the ice of the former glacier.
The rock was jointed or cracked during the uplift of the mountains and,
after the polishing of the upper surface, large blocks were broken off
along joint planes and carried away by the moving ice, leaving the
smooth face of the joint exposed. This was later polished by the
ice. |
| 11.0 | Glacial polish is visible about 150 feet
above the road showing the height of the former glacier. |
| 11.8 | In line with the road is Mount Chapin. The
banding of the old dark schist and the lighter granite, which as molten
rock was intruded into the schist when both lay deep within the earth,
is plainly seen. Mountain uplift and erosion have brought the rocks to
the surface and erosion working along joint planes has carved the
peculiar spires and pinnacles. |
| 11.9 | Granite broken into blocks by joints. These
were produced by the pressures and strains under which the rocks were
placed during the mountain uplift. |
| 14.0 | Surface of schist and intrusive granite
beside the road. These rocks have been ground smooth by the glaciers for
they formed the floor of the old glacial valley. The present stream
flows in a gorge which it has cut since glacial time, leaving part of
the old valley floor as a bench along which the road has been built.
The schist and granite were at one time so deeply
buried within the earth that the pressure upon them from all sides
exceeded the crushing strength of the rock. Under such conditions no
crevasses could form and during earth movement the rocks bent and flowed
like thick tar. Note that much of the bending took place after the
intrusion of the light granite. At one point a band of granite has been
folded and the fold, by continued lateral pressure, has been overturned,
broken, and one side thrust over the other. This type of thrust-folding
and faulting is characteristic of the mountain building which took place
at the end of the Mesozoic era when the Rockies were first formed. It
often happens that a single rock may show in miniature a type of folding
which is characteristic of an entire mountain range.
|
| 14.2 | Canyoncito (fig. 13). This little canyon has
been cut by the stream in the valley floor since the retreat of the last
glacier. Note that glacial grinding is evident on the terrace over which
the road runs, but that there is none in the little canyon. If we assume
that the glacial ice began to melt back from the valley below Horseshoe
Park some 25,000 years ago and retreated steadily to the cirques of Fall
River Pass, then it may have left this part of the valley some 10,000
years ago. If this reasoning is correct, it has required about 10,000
years for the stream to cut Canyoncito.
|
Figure 13.Canyoncito from Fall
River Road. There is glacial polishing on the surface of the rocks to the right, but the rugged gorge
shows no sign of glacial action. It is evident that the gorge has been
cut in the 10,000 years since the ice melted from this part of the
valley. Photograph by Carroll H. Wegemann
|
|
| 15.2 | Willow Park. This meadow was the bed of a
small lake impounded by a terminal moraine which marked a pause in the
retreat of the glacial ice. Such a moraine is known as a recessional
moraine.
In the next mile are numerous intrusions of
coarse-grained granitic rock known as pegmatite. The molten rock, deep
within the earth from which these intrusions solidified, probably
contained, under great pressure, much steam which made it thinly fluid.
It cooled slowly deep below the surface, giving the large crystals time
to grow.
|
| 17.0 | Large mass of pegmatitic granite several
hundred feet wide which has been intruded into the schist.
From this point an excellent view is to be had of
three cirques or basins in which glacial snow and ice accumulated at the
head of Fall River. From these the great glacier flowed down the
valley.
NOTE.Left hand column of figures below is for the use of travelers
coming up from Poudre Lakes.)
|
4.5 | 18.4 | Parking area at store and museum on Fall
River Pass. The cirques previously mentioned lie to the south, and
beyond them the ridge is capped by the remnants of an old lava flow
which is better exposed at Iceberg Lake (see p. 25, point 2.0
miles). |
FALL RIVER PASS TO POUDRE LAKES
There is not time on this circle trip to drive to
Grand Lake, but if you have an hour to spare turn right on the road to
Grand Lake, and use the right hand column of figures in log. Drive down
as far as Poudre Lakes on the Continental Divide. If you do not care to
take this trip but wish to go east down Trail Ridge Road, turn to page
24, point 0.0 miles in right-hand column.
|
4.0 | 18.9 | Overlook. Specimen Mountain, 3 miles to
the west across Cache la Poudre River, appears to be an extinct volcano
and the probable source of the lava previously mentioned. The mountain
is situated on the Continental Divide 2 miles north of Poudre Lakes and
can be reached by a trail from the Lakes. Erosion has long since
destroyed the old crater, which stood above the highest point of the
present mountain.
|
Figure 14.Volcanic Rocks of
Specimen Mountain, and the Never Summer Range, Specimen Mountain is an extinct volcano, its sides, as
shown in the foreground, formed by black pitchstone or volcanic glass,
white volcanic ash, fragments of rock blown out by the explosions, and
mud flows. The ancient crater has been destroyed by erosion. Photograph
by Carroll H. Wegemann
|
That the mountain was a volcano may be inferred from
the nature of the rocks which are exposed on its top and sides. Like
many volcanic cones, the mountain is built up of alternating layers of
black volcanic glass (pitchstone), lava, white volcanic ash, mud flows,
breccia, and pumice (fig. 14). Notes on the formation of these rocks
follow:
Volcanic glass is produced when molten rock
flowing out upon the surface is chilled so quickly that mineral crystals
do not have time to form in it.
Ordinary lava is cooled more slowly, but not
slowly enough for the rock to become completely crystalline like
granite, which is cooled very slowly far below the surface.
Volcanic ash is rock dust blown out by the
terrific explosions of the eruption.
Mud flows are formed when this dust is washed
out of the atmosphere by the torrential rains which frequently accompany
the eruption, the rains being due to the condensation of clouds of steam
emitted from the volcano.
Breccia is formed of fragments of the sides of
the crater, blown out during the explosions.
Pumice is lava charged with gas, the bubbles
of which expand when the pressure upon the lava is reduced as it reaches
the surface. The resulting small cavities when filled with air cause the
pumice to float on water.
All these rocks are to be seen on Specimen Mountain,
mute reminders of a time, in the distant past, when volcanoes were
active in this region.
The mountain was probably named for the opal, agate,
and delicate crystals of topaz which are found lining some of the small
cavities in the volcanic deposits.
|
1.2 | 21.7 | Exposed on the south side of the road,
about 400 feet beyond the end of the retaining wall, is greenish gray
soft rock which represents an old mud flow from the volcano. At higher
and lower levels along the road are the ancient rocks of the
pre-Cambrian era, and it is evident that the valley of the Cache La
Poudre and the lava flow at Iceberg Lake present interesting
relationships. Assuming that lava flowed from Specimen Mountain to
Iceberg Lake, it could not have done so had the valley of the Cache La
Poudre been present at the time of the flow. It is possible that the
lava at Iceberg Lake flowed from a vent other than that of Specimen
Mountain, but there is no evidence of such a vent. A possible
explanation is that the volcanic deposits from Specimen Mountain
completely filled an old valley which had been cut in pre-Cambrian rocks
at the location of the present valley of the Cache La Poudre; that, in
one of the last eruptions of the volcano, lava flowed across this fill
to what is now Iceberg Lake; and that subsequent erosion excavated the
present valley in the filling of the former valley, exposing some of the
old mud flows which were part of the filling and the much more ancient
rocks which formed the south side of the old valley. The mud flows,
therefore, are merely a veneer partly covering the more ancient
rocks. |
0.0 | 22.9 | Parking area at Poudre Lakes. These lakes
are on the Continental Divide although in a valley much lower in
elevation than Fall River Pass. A glance at the park map will show that
because of peculiarities of stream development the highest mountain
peaks are not always along the Continental Divide.
(NOTE.If you have entered the park from the
west, set your speedometer at 0.0 at the parking area at Poudre Lakes
and read paragraphs in reverse order up to 4.5 in the left-hand column
of figures. At Fall River Pass reset at 0.0 and continue as below.)
Returning to Fall River Pass, reset the speedometer
at 0.0 and use the right-hand column of figures. The left-hand column
is for the use of those driving in the opposite direction.
|
TRAIL RIDGE ROAD BETWEEN FALL
RIVER PASS AND DEER RIDGE JUNCTION
|
Miles |
|
22.9 | 0.0 | Road junction just southwest of museum
and store at Fall River Pass. If you are traveling east, keep right on
Trail Ridge Road. |
21.9 | 1.0 | Overlook on curve. To the west, across
the head of the valley of the Colorado River, rise the Never Summer
Mountains, 7 miles away. This overlook is at 12,000-feet elevation on
the Upper Flattop peneplain, an old erosion surface formed not far above
sea level and raised to its present elevation during the last uplift of
the region. Directly to the south, across Forest Canyon, rises the cone
of Mount Julian, the next prominent point to the west being Mount Ida,
the long northwest slope of which merges with the Upper Flattop surface.
Across the canyon and extending to its very rim is a bench about 500
feet below the Upper Flattop surface, the origin of which was described
in detail on page 10. It represents the beginning of a lower erosion
surface which was cut by the stream after the initial uplift of about
500 feet had taken place. Its presence records a considerable pause in
the uplift of the land before further elevation finally brought the
mountains to their present height. |
20.9 | 2.0 | Iceberg Lake. The rock which forms the
wall of the cliff back of the lake is red dish brown and differs in
appearance from the old pre-Cambrian rocks seen at other points on the
road. It is the same lava flow which was observed south of Fall River
Pass.
Looking north along the ridge, which is a
continuation of the cliff, it will be noted that there is pre-Cambrian
rock next to the lava and that it forms the north end of the ridge,
being rather poorly exposed in, and below, the north point on the
skyline. Across the highway, just south of Iceberg Lake, pre-Cambrian
rock is also exposed. The pre-Cambrian. therefore, borders the lava on
both sides. It is evident that the molten lava which solidified to form
the rock of the cliff must have flowed down a valley cut in the older
rock.
Southeast from Iceberg Lake there is an excellent
view of the Upper Flattop peneplain (fig. 4). When it was formed it was
not quite a plain, for above it rose a line of low rounded mountains,
the remnants of the first Rockies. The Mummy Range to the northwest was
part of the line. The northwest side of this range shows the old erosion
surface merging with the mountain slope. This surface is, however, being
rapidly destroyed by the streams which are cutting canyons into it from
the east. Farther to the south the group of mountainsIda, Julian,
and Terra Tomahappear to have been one rounded mountain rising
above the plain before the erosion of water and ice cut the canyon of
the Gorge Lakes into its heart. Stones Peak may have been part of the
same mass before it was separated from it by the cutting of the gorge of
Hayden Creek, the next gorge to the east.
On Trail Ridge, about half a mile to the southeast,
where the road follows the narrowest part of the ridge, the slopes on
either side look as if they were roughly terraced. The soil is but a few
feet thick and rests on a sloping surface of bedrock. In the spring when
the snow melts, or during heavy rains, the soil becomes saturated with
water which not only increases its weight but makes it slippery. Masses
of soil, bound together by plant roots, tend to slide gradually for a
few inches, or a few feet, down the slope, breaking away from the turf
above and overlapping the turf below, thus producing the
terraces.
|
18.6 | 4.3 | Rock Cut, 12,110 feet elevation. To the
southeast is the gorge of Hayden Creek. Directly south across Forest
Canyon the view is up the canyon of the Gorge Lakes. There are six of
these lakes in the canyon proper. One, at an elevation of 12,400 feet,
is the highest lake in the park. It occupies an old glacial cirque, the
cliffs of which shelter it from the sun's rays so that it is never free
of ice. The gorge itself was originally cut by streams but has been
entirely reshaped by the ice of former glaciers. It contains numerous
cirques. Its rugged outlines are in marked contrast to the old erosion
surface which, as already mentioned, forms the summits of the
surrounding mountains. Nor is it difficult to reconstruct in
imagination the shape of the rounded mountain mass before erosion gashed it
with cirques and canyons. The landscape of the old plain with its low
mountains must have been monotonous. The spectacular scenery of today is
due to the comparatively recent uplift of this region and to stream and
ice erosion. |
15.6 | 7.3 | Road crosses to Hanging Valley on north
side of Trail Ridge. There are three stone cabins north of road. To the
south, across Forest Canyon, is a view of Hayden Creek with several
abandoned glacial cirques, the collecting basins of former glaciers,
near its head. West of its mouth a great cirque has been cut into the
side of Terra Tomah, partly destroying the old erosion surface which
forms the top of this mountain. |
14.9 | 8.0 | The bark on the spruce, fir, and pine
trees at timber line where exposed to the wind-driven snows of winter
and the sand blasts of dry weather is worn off the windward
side. |
14.0 | 8.9 | Guard wall. To the west is Sundance
Mountain with a remarkably fine example of a glacial cirque cut into its
eastern flank (fig. 11). To the north across Fall River Valley the
switchbacks on the Fall River Road are visible. |
13.6 | 9.3 | Rainbow Curve affords a magnificent
panorama. To the north lies the Mummy Range. Its peaks, northeastward
from Fall River Valley, are: Mount Chapin, Mount Chiquita, Ypsilon
Mountain, Fairchild Mountain, and Hagues Peak, with Mummy Mountain
southeast of Hagues. Note on Ypsilon Mountain the banding of the dark
schist and the white granite which, as molten rock, was intruded into
it when both lay deep within the earth.
Below lies Horseshoe Park in the broad valley of Fall
River. Beyond the tree less meadow in the distance, which is a former
lake bed, a low wooded ridge crosses the valley (fig. 15, C4).
This is one of the terminal moraines of the Fall River Glacier
(Wisconsin stage). It was this natural dam which impounded the lake
waters and through which the outlet finally cut its channel, draining
the lake and leaving several small ponds in the irregularities of its
bed.
|
Figure 15.Horseshoe Park from
Rainbow Curve, Trail Ridge Road. A1, Big-Horn Mountain; A4, crest
of north lateral moraine of former Fall River Glacier, slopes east;
B2, The Needles, part of an old erosional surface at 10,000 feet
elevation; B6, bed of former lake impounded by terminal moraine;
C3; McGregor Mountain; C5, terminal moraine of Fall River
Glacier; C7; south lateral moraine which merges at east end with
terminal moraine; D3 Castle Mountain, part of old erosional
surface at 8,700 feet elevation; D7, beaver pond in Hidden Valley;
E2, flat top of Deer Mountain, part of same erosional surface as
that of The Needles. Photograph by Carroll H. Wegemann
|
On either side of the meadow rise the abrupt gravel
slopes of the lateral moraines, 800 feet in height, the tops of which
indicate the height of the ice in the valley (fig. 15, A4). They
slope eastward to the point where they merge with the crest of the
terminal moraine (see p. 29, point 8.2 miles).
From the north end of the terminal moraine the north
lateral moraine can be traced to the point where it crosses the valley
of Roaring River. This valley also was occupied by a glacier, but one
which apparently lacked the cutting power of the longer and straighter
Fall River Glacier, It was unable to lower the bed of its valley as
rapidly as did the glacier of Fall River, and the mouth of the side
stream was left hanging 400 feet above the bed of the major stream to
which it falls by a series of cascades, It is probable that the glacier
of Fall River continued its flow longer than its smaller tributary, for
it seems to have thrown its north lateral moraine across the Roaring
River Valley. After the glaciers disappeared the stream was able to cut
away part of this obstruction.
Note that almost no morainal gravel or sand was
deposited on the point of Bighorn Mountain which projects into the
valley and which felt the full force of the ice movement. The ice did
drop its load, where it was moving with less power, in the more
sheltered parts of the valley both above and below this point.
Turning now to the south lateral moraine (fig. 15,
C7), it is evident that this also threw a dam across the mouths of
the side valleys coming in from the south. These valleys did not carry
glaciers. Their waters were impounded by the moraine, back of which the
road now runs, and were forced to flow eastward south of the moraine.
The moraine is lower in this direction and the stream, which is called
Hidden Valley Creek, at length reached a point where its waters could
overflow the barrier and cascade down the moraine to the floor of the
main valley. This little stream is crossed on the road from Deer Ridge
Junction to Horseshoe Park. The beaver have built several dams across
the stream back of the moraine, their ponds (fig. 15, D7) being
plainly visible from this point.
The flat-topped mountain in line with the road is
Deer Mountain, along the base of which the road from Deer Ridge Junction
to Beaver Park is located. Its top and the top of The Needles are parts
of an old erosion surface similar in origin to the Flattop peneplain,
but formed somewhat later. A remnant of a still lower plain of erosion
is to be seen on the top of Castle Mountain, beyond and just to the left
of Deer Mountain. As explained on page 10, these old erosion surfaces
were formed, when the region stood at lower altitudes, by stream which
had reached their limit of down cutting and were widening their valleys.
These erosion surfaces have been for the most part destroyed by the
streams which produced them, after further uplift gave the streams more
fall and enabled them once more to deepen their valleys.
|
12.7 | 10.2 | Sign 2 miles above sea level. |
10.7 | 12.2 | A dike several feet wide of dark rock
known as dolerite has been intruded into the lighter granites and is
well exposed at the side of the road. The same dike is believed to have
been encountered in the Colorado-Big Thompson Diversion Tunnel which
passes under the Front Range. The molten rock that formed the dike was
forced into a fissure which apparently extended in a straight line for
several miles. What appears to be the same dike can be seen on the south
side of Mount Chapin. |
9.3 | 13.6 | Many Parks Curve. The description of the
Fall River Valley as given from Rainbow Curve (see p. 26, point 9.3
miles) applies equally well here. Note the excellent view of Longs Peak
to the southeast and of Moraine Park shut in on north and south by the
great timbered ridges of its lateral moraines. At the eastern end of
Moraine Park rises Eagle Cliff. From the flat floor of the park rises
the little granite island which is noted from point 0.7 miles. (See p.
18.) The treeless area to the north of Moraine Park is Beaver Park,
bordered on its north side near the lower end by a narrow tree-covered
ridge. This ridge is the lateral moraine of an older glacier which once
flowed down the Thompson Valley. (See description at point 2.4 miles,
p. 19.) This lateral moraine can be traced farther west by the thin line
of trees which divides Upper Beaver Park. |
7.8 | 15.1 | Curve into Hidden Valley. To the north
lies the south lateral moraine of the Fall River Glacier which has
dammed Hidden Valley and forced its waters to flow east as Hidden Valley
Creek along the sooth side of the moraine. The road also follows the
moraine. |
7.6 | 15.3 | Beaver dams. |
6.8 | 16.1 | Cross Hidden Valley Creek. The gravel
and sand of which the moraine is built are exposed in the road cut on
the left. |
6.0 | 16.9 | Hidden Valley Creek has cut through a
low point in the moraine on the left and drops by a series of cascades
(not visible from this road but noted at point 5.9 miles (page 20) some
400 feet to the bed of Horseshoe Park. |
5.3 | 17.6 | Deer Ridge Junction. This completes the
circle trip. You may return to Estes Park by the paved road to the right
or by Route 34 to the left. If the latter route is taken, set the
speedometer at 5.3 miles. |
DEER RIDGE JUNCTION TO FALL
RIVER ENTRANCE VIA HORSESHOE PARK
|
Miles |
|
| 5.3 | Deer Ridge Junction. Take road to left
(north). For details of the log between this point and point 7.1 miles
below see page 20. |
| 7.1 | Junction in Horseshoe Park with road to Fall
River Pass. Keep right on Route 34. |
| 7.3 | Sheep Lake, a shallow pond in a depression in
the floor of the ancient lake. Just beyond, the road climbs to one of
the old lake terraces described at point 6.8 miles, page 20. There is
another terrace 25 feet higher. These terraces are old shore lines
formed when the former lake stood at high levels. |
| 8.2 | Terminal moraine (Wisconsin stage) which
impounded the ancient lake until the outlet cut its channel through it,
draining the lake waters. |
| 8.4 | Studio of David Stirling. |
| 8.8 | East base of terminal moraine. |
| 8.9 | Road follows, and cuts into, a north lateral
moraine of what appears to be a glacier older than the Wisconsin, and
which extended some distance farther down the valley than did the
Wisconsin ice. |
| 9.2 | Fall River Entrance to Rocky Mountain National
Park. |
| 9.3 | Side road to Bryson Cottages crosses the
valley on recessional moraine. |
| 9.5 | Small meadow, probably the bed of a former
lake, lies between two recessional moraines which here cross the valley.
McGregor Mountain on north shows, in its bare dome-shaped crest, the
typical weathering of granite, the surface of which spalls off in convex
slabs. |
| 9.8 | Fish hatchery and bridge. |
| 11.0 | Approximate end of glaciation. Below, the
valley narrows abruptly and is apparently unglaciated. |
| 13.9 | Estes Park. |
|
Figure 16.West side of Longs Peak
with Glacier Gorge below. Photograph by Carroll H. Wegemann
|
BEAR LAKE ROAD
A short but interesting drive is that to Bear Lake.
Set your speedometer at 0.0 miles.
|
Miles |
|
| 0.0 | Thompson River Entrance to the park. Take left
hand road inside entrance and cross Thompson River to Camp
Woods. |
| 0.4 | Tuxedo Park. Road follows the outside base of
the south lateral moraine of the Thompson Glacier (Wisconsin stage).
South of this moraine the surface of Tuxedo Park is covered by very old
morainal deposits of a glacier much older than the Wisconsin as shown by
the disintegrated condition of the morainal gravel. This glacier was
wider than was the Wisconsin Glacier and its deposits, therefore extend
beyond those of the Wisconsin ice. |
| 0.5 | In repairing a washout on the north side of the
road at this point in 1935, human bones believed to be those of a woman
were found several feet below the surface. They are said to have been
scattered and mixed with charcoal and rested on a bed of white sand
which may have been glacial outwash. The body was apparently cremated
on the surface of the outwash from the glacier and the remains later
covered by material washed down from the morainal ridge to the north.
The information is insufficient to warrant positive conclusions, but the
bones were probably very old. The skull is preserved in the Moraine Park
Museum. |
| 1.5 | Across the stream flat to the left is the
terminal moraine of the former Bartholf Glacier which flowed down the
valley of Glacier Creek. |
| 1.7 | Stream cuts through this moraine. |
| 2.0 | Fork. Keep left, crossing Mill Creek, and
climb the east slope of the terminal moraine of Bartholf
Glacier. |
| 2.5 | Crest of moraine. |
| 2.9 | West base of terminal moraine. Road follows
the south side of the north lateral moraine of the Bartholf
Glacier. |
| 3.3 | Fork. Take left road to Glacier Basin
Campground, a broad treeless flat which was the melting basin of the
Bartholf Glacier. From this flat there is a commanding view of the
Continental Divide and of the high, even-topped ridge formed by the
north lateral moraine of the Bartholf Glacier.
The ridge ends on the west against the side of
Flattop Mountain for which the Upper Flattop peneplain has been named.
From this observation point it is difficult to appreciate fully the
flatness of the mountain's top.
The first sharp peak on the skyline to the left of
Flattop Mountain is Hallett Peak and in the cirque to the right of it
lies Tyndall Glacier.
Left, or south of Hallett Peak, is Otis Peak, and
just left and back of the latter, but hidden from view in the gorge,
lies Andrews Glacier.
Note that the smooth side of Otis Peak slopes to the
north and that a similar surface on Hallett Peak slopes to the south.
These smooth surfaces appear to be the sides of one of the old erosion
valleys cut in the Flattop peneplain after the initial uplift of that
surface when the bench was formed at the head of Forest Canyon (see
point 1.0 mile, p. 24). A similar surface appears on Thatchtop Mountain
which is the second peak south of Otis and is nearer this point. To the
right of Thatchtop and farther away is Taylor Peak and between them is
the glacial valley of Loch Vale, U-shaped in cross section, containing a
series of glacial lakes and Taylor Glacier hidden from view at its
head.
East of Thatchtop Mountain lies Glacier Gorge, and
east of that is Half Mountain against which rests the west end of the
south lateral moraine of the Bartholf Glacier which rims Glacier Basin
on the south. Beyond the long even crest of the moraine rises in
majestic grandeur the flat summit of Longs Peak, 14,255 feet in
elevation. Its perpendicular cliffs are the walls of ancient
cirques.
Returning from Glacier Basin Campground to the main
road, reset the speedometer at 3.3 miles. Turning left (west), continue
the log. On the right rises the long ridge of the north lateral moraine
of the Bartholf Glacier.
|
| 3.6 | Road cuts across a jutting point of this
moraine. |
| 4.0 | Road to Sprague's Lodge. Keep straight
ahead. |
| 5.1 | Trail to Bierstadt Lake which is on top of the
great accumulation of moraine lying north of the Bartholf
Glacier. |
| 6.1 | Prospect Canyon. The old tunnel, driven in a
futile search for minerals, is at the edge of an intrusive dike, here
poorly exposed. Prospect Canyon is a small but abrupt gorge cut by the
stream since the retreat of the glaciers from the valley. |
| 6.9 | Glacier Gorge parking area, from which road
climbs moraine. |
| 7.2 | View of head of Glacier Basin Valley, its
surface strewn with the deposits of former glaciers. These deposits have
been trenched by recent streams since the retreat of the ice. |
| 7.7 | Parking area at Bear Lake, This beautiful body
of water occupies a depression between the rock cliffs which rise on its
west side and the moraines of various ice advances on the north and east
and south. It lies in the line of flow of the former Tyndall
Glacier. |
This is the end of the road and you must return down
the valley by the same road up which you came.