I could not find any specific information regarding the thickness of Crowsfoot Schist slabs in the United States. However, Schist is known for its foliated structure, and the thickness of the slabs can vary depending on the quarry. The thickness can range from a few centimeters to several meters. It is best to consult a geologist or a local quarry for specific information on the thickness of Crowsfoot Schist slabs in your area.