After traveling along the trail for about five to ten minutes you will descend into some low lying areas. Some of these areas collect water and have been made more accessible with boards.
A little further down the path, you will come upon Mary Bird Branch Tributary, which empties out into South Fork Quantico Creek. There is a small bridge crossing over the creek.
At Mary Bird Branch there are opportunities to see beaver activity. From the 1600s through the 1800s, there was a high demand for beaver skins, and the once-thriving population was severely diminished. In fact, beavers disappeared from the Virginia colony even before it became the Commonwealth of Virginia. Soon, beavers became extirpated (extinct from an area) across the entire lower 48 states.
In the early 1950s, two pairs of beavers were brought in and released along Mary Bird Branch. This stream does not always maintain a heavy flow of water from year to year, so the beavers move on to other, more suitable, locations in the park. When the water level is high once again, they return.
The result of the beaver activity is the creation of new fertile habitats for plants and animals. There are many stages of habitat changes brought about by beavers along this stream. As you walk along the stream, see if you can locate older pond sites by the absence of a tree canopy and an abundance of new sprouts from gnawed stumps.
From here it is only a short walk up to Old Black Top Road.