THE LARAMIE SERIES. 85 



should be classed with the Cretaceous or the Eocene, since they c<intain 

 reptilian fossils of Cretaceous types, raollusks' allied partly with the Creta- 

 ceous and partly witli the Eocene, and a flora resembling- that of the 

 Miocene in Europe. From the presence of beds of lig-nite coal, the name 

 Lignitic was formerly often applied to this formation. 



In the Missouri and Saskatchewan region the Laramie series consists 

 mainly of sandy shales and sandstones. The similar strata in the vicinity 

 of the Bow and Bell)' rivers, referred to the Laramie by Dawson, have a 

 thickness of 5,750 feet, and are wholly fresh-water deposits except near 

 their base. On the Missouri River this series reaches from near Bismarck 

 westward by Fort Union and across the Yellowstone to the Milk and 

 Musselshell rivers. At Sims, on the Northern Pacific Railroad, about 40 

 miles west of Bismarck, it contains a layer of lignite 8 feet thick, which is 

 extensively mined. Northward the Laramie series occupies the upper jior- 

 tion of the basin of the Souris or Mouse River, and forms the Missouri 

 Coteau to the Canadian Pacific Railway and the South Saskatchewan, and 

 probably will be found continuous northwest along this coteau to the North 

 Saskatchewan. Near the base of Turtle Mountain, which beneath its thick 

 covering of drift is an extensive outlying area of Laramie strata, also on 

 the Souris, and on the Bow and Red Deer rivers, head streams of the 

 South Saskatchewan, the lower part of this formation bears Avorkable 

 seams of lignite, apparently on nearly the same horizon with the mine at 

 Sims, in the central part of North Dakota. 



The western jilains a lacustrine and land area since the earli/ part of the 

 Laramie epoch. — Miocene conglomerate, sandstone, and sandy clays, of 

 fluvial and lacustrine deposition, are found lying- on the Laramie and other 

 Cretaceous fonnations in the Hand Hills, northeast of Red Deer River, and 

 in the Cypress Hills, between the South Saskatchewan and Milk rivers. 

 They are remnants of strata that jjrobably once thinly overspread consid- 

 erable portions of the upper Saskatchewan region. Five hundred miles 

 southeast from the more southern of these localities an extensive area of 

 fresh-water Tertiary deposits, of Miocene and Pliocene age, begins on 

 White River, in the southwestern j^art of South Dakota, and reaches south- 

 ward throug-h Nebi-aska to western Kansas. No marine Tertiary formations 



