"Catoctin Rocks!", Correct Answer to Question 3: Triassic Border Fault


Question 3. What is the name of a major fault in this area?

Answer: Triassic Border Fault.

Around 200 million years ago, during the Triassic period, beds of rock broke along what is now U.S. Route 15 and created a Triassic Border Fault. West of the fault, the land moved up and was eroded to become Catoctin Mountain. East of the fault, the land slid down and is now the Frederick Valley.

Congratulations, you have completed the "Catoctin Rocks!" activity!

Last updated: April 10, 2015

Contact the Park

Mailing Address:

6602 Foxville Road
Thurmont, MD 21788


(301) 663-9388

Contact Us