78 STEVENSON— INTERRELATIONS OF FOSSIL FUELS. 



Hills. The relations of the Lance formation have been subject for 

 much discussion ; the testimony of plant and animal remains is con- 

 tradictory. In no inconsiderable area, the Lance is conformable to 

 the Fox Hills. Winchester in a recent note, summarizing results 

 obtained by himself and his assistants, in eastern Wyoming, states 

 that Lance overlies Fox Hills. It is subdivided into three members ; 

 a lower undifferentiated portion, 425 feet thick ; a middle, lignite- 

 bearing portion, the Ludlow, at least 350 feet ; and an upper marine 

 member, the Cannonball, 225 feet. The marine fauna of the Can- 

 nonball is very similar to but not identical with that of the Fox Hills, 

 while flora of the Ludlow cannot be differentiated from that of the 

 Tertiary Fort Union. ^^ 



The eastern half of Montana is a rolling plain covered with Ter- 

 tiary and later deposits, the mountains of states at the south having 

 disappeared. Anticlinals have brought up the highest members of 

 the Cretaceous. The Lance, taken by the writer as the eastern ex- 

 tension of the Laramie, has at base the Colgate sandstone, which is 

 90 to 175 feet thick and contains no coal except at one locality, 

 where Hance saw a lens only a few hundred yards long. The 

 upper part of the Lance, about 500 feet, has variable seams of lig- 

 nitic coal, but all are lenticular. Some observers note great irregu- 

 larity in the deposits, which appear to be fresh-water throughout.^'' 



West from the 109th meridian, one approaches the mountain re- 

 gion and finds the whole Cretaceous exposed. In northern Fergus 

 County, the Lance appears to be present, but the relations of the 

 beds are not altogether clear. Near the Crazy Mountains in 

 Meagher County, Stone found 1,200 to 2,800 feet of shales and 

 sandstones, which he places in the Laramie ; but the Lennep sand- 

 stone, at the base, 200 to 400 feet thick, is known now to be Fox 

 Hills. Lenses of coal, a few inches thick and of insignificant hori- 

 zontal extent, are present in the Laramie. Not far westward from 

 this district shore conditions prevail and a continuous formation, 



38 E. G. Woodruff, Bull. 341, 1909, pp. 202, 205; Bull. 381, p. 173; C. W. 

 Washburne, Bull. 341, pp. 167, 169, 181 ; C. H. Wegemann, Bull. 471-F, 1912, 

 pp. 2(i, 30; D. E. Winchester, Bull. 471-F, p. 58; Journ. Wash. Acad. Sci., Vol. 

 VII., 1917, p. 36; N. H. Darton, Prof. Paper 65, 1909, p. 58. 



sow. R. Calvert, C. F. Bowen, F. A. Herald, J. H. Hance, Bull. 471-D, 

 1912, pp. 13, 21, 48, 49, 91. 



