Answer to Question 1Although many of the rocks on Turtle Mountain dip away from the valley, the joints in the massive
limestone composing Turtle Mountain dip steeply toward the valley, so they are parallel with the
mountain's slope. The rocks are weak limestones, shales, and coal layers that underwent slow plastic
deformation from the weight of the overlying limestone. Coal mining along the base of the valley
removed some of the underlying support. Frost action and chemical weathering widened the joints, and
a rock slide resulted.
Answer to Question 2Wire mesh is put on slopes to prevent dislodged rocks from falling onto the road below. Rockfalls
result from failure of bedrock along joints or bedding planes and occur because the slope has been
undercut (often by building the road). Rocks can be small to massive and can even bury towns