Sunday. Continuation of section described in preceding page described by Prof. Miller. Heights are barometric. Conglomerate gravel Purins clerty fragments Shale Grey crystalline limestone Criminal. Clerty shaly limestone. Dark chert or flint. Sandy shale, more irregular and calcareous at top. x Nodular layer Black shale. Thin bedded Madison Thick bedded Mad Richmond beds 22 10 40 brams. 17 Sunday. Certhia biforata occurs in the thick- bedded Madison bed from 3 feet above the base to 7 ft above the base. It is rare but can be found. 14 specimens were found between the anticlinal and the place called the ripple on the map. The branching byrgans are found from 5 feet above the same to 7ft 10 inches above the same, 15 specimens found. The globular byrgans are found from 5.2 feet to 6.2 feet above the base of the heavy Madison beds. Considering the fact that the heavy Madison beds are 9 ft 2 inches thick time, it will be seen that five Siluria fossils are found through its entire thickness. Moreover the thickbedded Madison is lithologically the same as the overlying thin bedded Madison, but the thin layers hang together and therefore have a total massive effect and break off in larger masses from the cliffs. Hence the beds are often 1 inch thick while the beds of the thin bedded Madison are often only ½ inch thick. Note the absence of the 26 inch blue limestone layer (R) from above the Madison. This denotes that the Black Shale does not lie on the top of the Madison, one of the Madison having been removed by erosion. The Richmond beds contain chiefly Certhia biforata, and hyrgans. Certhia occidentalis is rather uncommon.