46 



ANNALS NEW YORE ACADEMY OF 8CJENCES 



Section east of Lyons, Colorado 



Feet 

 "Dakota," Sandstone, hard massive, buff. . 

 Olive green massive sbale, vs^itli 



some sandstone layers 150 



Light grayish green massive 



shale 30 



Soft to hard gray sandstone, 



fine grained 15 



Red, maroon, and green massive 



shale 150: 



Morrison, Massive buff sandstone, moder- 

 ately fine 10 



Grayish green to maroon mas- 

 sive shale, with thin layers of 



fine grained sandstone 40 



Covered 25 



Upper Wyoming, Soft buff sandstone 30 



Fig. 3. — Section of the Morrison and over- 

 lying and underlying Jjeds at Laporte, 

 Colorado. 



Fig. 4. — Section of the Morrison and ad- 

 jacent formations east of Lyons, Colo- 

 rado. 



A-B 



Morrison. Scale, 125 feet to 1 1. — Lakota ; 2. — Morrison ; 3. — Red Beds. 

 incli. (Darton.) Scale, 125 feet to 1 inch. (Darton.) 



The Morrison formation in the vicinity of Bonlder was described by 

 Fenneman (1905, 9). The following remarks on the formation in this 

 district are based on Eenneman's description. Sections of the Morrison 

 at various places in this area differ greatly. In the main, however, the 

 formation contains a large proportion of light-colored clays, some mod- 

 erately indurated and others of flinty hardness, much gray sandstone, 

 often calcareous, and at various horizon's beds of highly compact lime- 

 stone. A very much generalized section would present the beds in about 

 the following order, beginning at the base : sandstone, clays, limestone, 

 clays. The first and last members of the series are persistent, but the 

 intervening clays and limestone may show two or three alternations and 

 may inclose prominent sandstones. Fenneman estimates the maximum 

 thickness to be a little less than 400 feet. The formation in this district 



