52 



ANNALS NEW YORK ACADEMY OF SClENCEii 



about 5 feet on the average, and the variation in thickness is not great. 

 Two distinct types of cross-bedding are present in this sandstone. It is 

 underlain by a bed of clay 1 or 2 feet thick. This clay is underlain by 

 another sandstone with a lense-shaped cross-section. It is about 15 feet 

 thick at its thickest portion and about 2 feet thick at a point 60 or 80 

 feet on either side of its center.- Below this sandstone is a bed of clay, 

 8 feet thick, bearing small obscure shells. Below this clay is a limestone 

 1 foot thick, which is underlain by 9 feet of clays. These clays are under- 



lie 11.- 



-27(6 Cope dinosaur quarry northioest of the Marsh-Hatcher quarry, near 

 Canon City, Colorado. 



lain by a bed of lime concretions, 1 foot thick, underlain by more clays. 

 The beds below are not exposed in the gulch, but are exposed on the west 

 bank of Oil Creek about a hundred yards northeast of the quarry. The 

 section at this point is as follows : clays at the top, underlain by about 

 3 feet of sandstone, which are in turn underlain by about 5 feet of the 

 bone-bearing sandstone. Below this are 3 feet of the quarry-floor sand- 

 stone. There is a sharp contact between this sandstone and the under- 

 lying clays. Below the quarry-floor sandstone there is a series of beds. 



^ See discussion of strvictures, p. 117. 



