Occasional Papers of the Museum of Zoology 3 



to Mr. A. H. Eastgate, of Bottineau, and to Mr. Charles East- 

 gate, County Agent of Slope County, whose hospitality and 

 generosity in the matter of furnishing transportation and 

 information concerning local conditions made possible a 

 greater degree of success in the field work than would other- 

 wise have been attained. 



Notes on the Major Environmental Conditions 

 In order that the environmental conditions governing the 

 distribution of the Orthoptera within the state may be better 

 appreciated, the following brief sketch of the physiographic 

 conditions found within its boundaries is given. It is taken 

 chiefly from the detailed reports of Simpson^ and Leonard. - 

 The surface of the state of North Dakota consists of three 

 well-marked plains which rise successively from east to west 

 by distinct escarpments, these being the Red River Valley, the 

 Drift Prairie Plain, and the Great Plains Plateau. The first 

 two of these physiographic regions are placed by Fenneman-' 

 under the Western Lake Section of the Central Lowland 

 Province; the westernmost and highest as a part of the Mis- 

 .souri Plateau Section of the Great Plains Province. 



The Red River Valley occupies a comparatively narrow 

 strip running north and south along the eastern edge of the 

 state, with an elevation above sea-level of from 800 to 975 

 feet. It is bounded on the west by an escarpment 300 to 500 

 feet high, known in the northern part of the state as the 

 Pembina Mountains, and in South Dakota as the Coteau des 



1 Simpson, H. E., 1912, The Physiography of the Devils-Stump Lake 

 Region, North Dakota. Sixth Biennial Report, Stale Geological Sttr- 

 vey of North Dakota, pp. 103-157. 



- Leonard, A. G., 1908, The Geology of Southwestern North Dakota, 

 . . . etc. Fifth Biennial Report, State Geological Surz'ey of North 

 Dakota, pp. 27-114. 



"^ Fenneman, N. M.. 1916, Physiographic Divisions of the United 

 ■ States. Ann. Assoc. Amer. Geogr., vi, pp. 19-98 (3-2. 61). 



