MOOK, STUDY OF THE MORRISON FORMATION 



ol 



steep cliff on the western border of Garden Park. At this latter point 

 the beds are exposed from base to summit, affording a complete section. 

 Several productive bone quarries have been operated at this point, and as 

 these quarries exhibit the structure of the formation very well in some 

 cases, they will be described in detail. The most important of these 

 quarries is that which was operated by Professor 0. C. Marsh, and later 

 by J. B. Hatcher for the Carnegie Museum. This quarry is situated on 

 the northeast l^ank of a dry brook-bed which joins Oil Creek ju=t south 



>S£-^W' 



i 





- ' " — .'^ i Mr * | *>'- - 



Fig. 10. — Exposure of the lower beds of the Morrison formation about lUO yards 

 northeast of the Marsh-Hatcher dinosaur quarry, near Caiion City, Colorado. 



of the entrance to Garden Park. The uppermost beds exjjosed at the 

 quarry are red and brown joint-clays. Below these clays is a bed of 

 rather coarse, heavy-bedded sandstone, about 5 feet thick. Below this is 

 the bone-bearing sandstone, about 3 feet thick. It is a soft, coarse- 

 grained sandstone, somewhat arkosic. In the exposures on the opposite 

 side of the gulch the bone-bearing sandstone is distinctly cross-bedded. 

 Below the bone-bearing sandstone is the sandstone of the quarry floor. 

 This sandstone is heavy-bedded and is cross-bedded on a large scale. This 

 cross-bedding makes the exact thickness difficult to determine. It is 



