MOOK, STUDY OF THE MORRISON FORMATION 



53 



36 feet in total thickness, which is mostly clay, but may contain thin beds 

 of limestone or concretions where it is covered by a thin clay tains. Be- 

 low this clay series is a heavy-bedded sandstone about 8 feet thick. This 

 sandstone is underlain by a series of clays interbedded with thin layers 

 of limestone and nodules. This series may be taken as the base of the 

 Morrison formation in this region. It is underlain by the reddish arkosic 

 sandstones of the underlying formation. 



Another important quarry in this region is that operated for Professor 

 E. T). Cope in 1877. This quarry is situated about GOO yards northwest 



Fig. 12. — The "Nipple/' west of Garden Park. Colorado, looking east. 



of the Marsh-Hatcher quarry. It is situated at the top of the hill, and 

 the beds exposed in it are the brown and white clays. of the uppermost 

 beds of the Morrison formation in this district: They are overlain by the 

 coarse white sandstone of the Lakota or Purgatoire formation. The con- 

 tact between the two formations is very sharp. 



Another quarry operated for Professor Cope is situated about 500 yards 

 east of the above-mentioned Cope quarry. It is situated at the base of a 

 small conical hill, locally known as the "Nipple." It is at the top of the 

 cliff which forms the Avestern boundary of Garden Park. The productive 



