The Hurricane Lentil in the lower part of the Landrum Member of the Cook Mountain Formation can be recognized for 170 miles along strike. This lentil lies at the base of the Landrum Member and is directly above the Wheelock Member. Three key beds, two bentonites and a fossil bed containing Plicatula filamentosa Conrad , are present at most exposures of the Hurricane Lentil. Sedimentary rocks of the Cook Mountain Formation are classified using the four common constituents: quartz, iron oxide, glauconite pellets, and clay. The abundant fossils in the Hurricane Lentil indicate deposition took place on the continental shelf in a quiet, open marine sea with a level bottom. The lower Hurricane Lentil was deposited in a relatively stable sea whereas the upper Hurricane Lentil was deposited in a regressive sea. / text