548 



NATURALIST'S GUIDE TO THE AMERICAS 



N. D., one mi. G. N. R. R. M. R. 

 Gilmore. 



*N 'alive Prairie. (A4.) Hillside and 

 valley. This is an excellent specimen 

 of undisturbed and unspoiled native 

 prairie. Gift to the State Historical 

 Society of North Dakota. About 1600 

 ft.; 5 acres. Preserved by the State. 



(a) Jamestown (1), Stutsman County, 

 N. D. 5 mi. N. P. R. R. M. R. 

 Gilmore. 



* Deciduous Forest and Prairie. (H8.) 

 Flood plain. Alluvium. Site of old 

 Ft. Abercrombie is nearby. Not much 

 trace of original vegetation is left. 

 Gift to the State Historical Society of 

 North Dakota for historical park. 

 935 ft.; 6.25 acres. Preserved by the 

 State. 



(w) (a) Abercrombie (1), Richland 

 County, one mi. C. M. & St. P. R. 

 R. M. R. Gilmore. 



Petrified Forest. Area of 25 to 100 

 sq. mi. Arid grassland on Bad Lands. 

 Many fossil tree stumps. 15 mi. north- 

 west of Medora, North Dakota. In- 

 quire Mr. Carl Olsen, Peaceful Valley 

 Ranch, Medora. Reached by wagon. 

 Crystal Thompson. 



Reference: 



Bergman, Herbert F. Flora of North 

 Dakota. 1917. 6th Biennial Report, 

 N. D. Soil and Geol. Surv. 



8. SOUTH DAKOTA 



BY E. J. PETRY AND S. S. VISHER 



I. GENERAL CONDITIONS (E. J. P.) 



South Dakota, 400 mi. (east and west), 

 is a part of the Great Plains and prairie 

 which stretch from the foothills of the 

 Rocky Mountains almost to the Missis- 

 sippi River. The state contains lakes, 

 small canyons, buttes, badlands and 

 mountains of great interest to the 

 traveler and scientist. The Missouri 

 River divides the state into two nearly 

 equal eastern and western parts, which 

 differ widely in their soils, geologic 

 and biologic features. 



The eastern half, except a small area 



in the southeast, is underlain by Creta- 

 ceous strata, while its soils consist of a 

 fertile dark brown loam of glacial origin, 

 which originally constituted a great 

 prairie, but which is at present almost 

 entirely taken up by farms. 



Throughout the northeastern part of 

 this section are found many small lakes 

 surrounded by deciduous groves, while 

 in the southeast, where outcrops of 

 Proterozoic age (Sioux quartzite) occur, 

 there are several streams, notably the 

 Big Sioux River, whose banks are 

 picturesque palisades and cliffs of 

 unexpected height and beauty. From 

 50 to 75 mi. west of the Big Sioux and 

 running parallel with it is the James, 

 or Dakota River, which meanders 

 through an unbroken plain about 1200 

 ft. above sea-level at the south and 1500 

 ft. at the north. 1 Like the Big Sioux, 

 its banks and flood plains are partly 

 wooded. 



The western half of the state, begin- 

 ning at the Missouri River, may be 

 divided conveniently into four general 

 regions. It consists essentially of a dry 

 plain rising gradually from an elevation 

 of about 1400 ft. in the east to 3500 ft. 

 near the western boundary. This plain 

 is traversed by five nearly parallel 

 rivers which meander eastward and 

 empty into the Missouri River. 



a. The northwest quarter 2 of this 

 plain is interspersed with stony buttes 

 several hundred ft. high, and shows 

 rugged outcrops of Tertiary and Creta- 

 ceous formations (Laramie and Fox 

 Hills), including clays, lignite, and sand- 

 stone of from 200 to 400 ft. aggregate 

 thickness. 



6. The second and largest area is 

 mostly of Cretaceous (Pierre Shale) 

 origin and stretches across the state 

 along the Missouri River, but narrows 

 abruptly toward the west till it occupies 

 the middle third of the plain and finally 

 divides, one arm passing to the north 

 of the Black Hills area, the other to the 



1 Barton, N. H. Geology and Underground 

 Waters of South Dakota. U. S. Geol. Surv., Water 

 Supply Paper 227, 1909, 156 pp., 15 plates, inch maps. 



2 Visher, S. S. The Biology of Harding County 

 Northwestern South Dakota. S. D. Geol. Surv., 

 Bull. 6, 126 pp., 1914. 



