100 ANNALi^ NEW YORK ACADEMY OF SCIENCES 



60 to 70 feet ; near Tilford and Piedmont, 40 feet ; south of Eapid, 30 to 

 50 feet; a mile north of Eapid, 150 feet; in the Bellefourche region, 10 

 to 30 feet (not clearly separated from the Sundance) ; very thin in the 

 Aladdin and Sundance regions. It is usually clearly separable from the 

 Sundance below and the Morrison above. 



The Unkpapa is usually soft, white, buff, red or purple in color; it 

 contains considerable material, and is often strongly banded. This band- 

 ing is usually parallel with the bedding, but occasionally makes a marked 

 angle with it. The rock is extremely porous and often exhibits interest- 

 ing examples of microfaulting in hand specimens. 



The name "Beulah shales" has been applied to the Morrison of the 

 Black Hills region. The formation consists of the usual series of clays 

 and shales, with thinner layers of sandstone and calcareous nodules. The 

 prevailing color is gray, biit other colors, such as red, maroon, pink and 

 purple sometimes occur. Carbonaceous matter is sometimes present in 

 the upper members. The following thicknesses of the Black Hills Morri- 

 son are given by Darton: near Eapid, 165 feet; east of Piedmont, 220 

 feet; rapidly decreasing to 70 feet in nearby locality; 4 miles north of 

 Tilford, 110 feet; 1 mile south of Eapid, 90 feet; 3 miles south of Eapid, 

 165 feet; in the region about Sundance, 150 feet; at Aladdin, 60 feet; 

 east of Aladdin, 80 feet or more; in Eedwater Valley southwest of Belle- 

 fourche, 50 feet; near Lookout Peak, 100 feet; about Table Mountain 

 and north of Eothen, 150 feet; near Alva, about 100 feet; in Barlow 

 Canyon, 85 feet; 3 miles north of Hulett, 150 feet; on Miller Creek, 7 

 miles southeast of Devils Tower, 160 feet. The thinnest section recorded 

 is in Barlow Canyon north of Devils Tower, the thickness there being 40 

 feet. Dinosaur bones of great size have been found in the Morrison near 

 Piedmont, apparently belonging to a sauropod of great specialization, re- 

 sembling Diplodocus. 



In the Newcastle quadrangle the Morrison deposits are mostly of light 

 gray color, but some portions are buff, pale green and maroon. The 

 thickness averages a little more than 150 feet and is greatest in the north- 

 ern part of the quadrangle. The beds outcrop along the inner side of 

 the hog-back below the Dakota conglomerate and sandstone. In the 

 region east of Salt Creek they occur in extensive outliers overlain by pro- 

 tecting caps of Dakota, and in the sloping plateau north of N'ewcastle 

 they are revealed in the deep canyons. The outcrops are often obscured 

 by talus derived from the sandstone cliffs above and by wash along the 

 slopes. The contact loith the Sundance shows an abrupt change in the 

 character of the material. At Cambria a drill hole in the floor of the 

 coal mine penetrated 12 feet of sandstone with coaly layers at the base 



