181 Where the road to Gravel Switch leaves the Rolling Fork road the Lower Silurian Alyps southwest, distinctly. 180 A mile south of Gravel Switch the Black Shale rests on the Corniferous at 1095. The Cornif- erous is 8 1/2 feet thick. The upper 2 1/2 feet are dark brown and fully calcite masses. The lower six feet are gray, a coarse chert layer occurs 1 foot above the base. The Cor- niferous rests directly in the Madison beds; 15 feet of Madison rocks were pierced there is a strong wet bond up. 179 Half a mile south of Gra- vel Switch, the Black Shale rests on the Cornif- erous at 1098. The Cor- niferous rest directly in the Madison, 178 A quarter of a mile S. y Gravel Switch the Black Shale rests on the Corniferous at 1130. 131 179 Just south of Gravel Switch the Black Shale rests on the Corniferous at 1170. - RR level at Gravel Switch is 1170. 189 Just south of Aliceton, on the west side of the road is the house of Shelby Cal- vert. NW of the Gravel Black Shale rests on the Cornif. erous at 1190. The Cornif. erous is 10 feet thick. The upper 4 feet are dark brown in color, contain calcite masses but few fossils. 6 feet below the top is a heavy chert layer 3-4 inches thick. The lower 6 feet are a light colored limestone only sparingly crinoidal. The Corniferous rests di- rectly in Madison; the top joint layer which contains chert, petro fritsima.