48 Proceedings of the 



6, The cool wooded ravines with springs and brooks. 



7. The bluffs with open woods and shrubbery and occa- 



sional vertical clay banks, largely artificial in origin. 



II. The prairie region. 



1. The larger streams, generally broad and shallow and 



with shifting sand-bars and sandy mud-flats. 



2. The smaller streams with steep, muddy banks. 



3. The prairie ponds, with marshes and mud-flats, fre- 



quently alkaline. 



4. The fringe of straggling timber and shrubbery along 



the streams. 



5. Thickets of plum and other shrubs back from the 



streams, on higher ground, and following up the 

 draws. 



6. The open prairie, with weed patches, especially at the 



heads of the draws. 



7. Planted groves. 



This region follows up the river valleys into the sand-hill region. 



III. The sand-hill region. 



1. The open sand hills, with "blow-outs," where the wind 



has scooped out a sandpit, often twenty-five to fifty 

 yards across. 



2. Shrubbery here and there in sheltered pockets in the 



hills. 



3. Wet valleys with hay flats, sloughs and marshes. 



4. Lakes with sandy, marshy or boggy shores. Mostly 



without outlets. The streams which lead out of this 

 region head in such lakes or bogs or marshes. 



5. Tree-claims and groves about the ranches. 



IV. The plains region. 



1. The open level plains. 



2. The few streams running frequently in more or less 



narrowed, often rock-walled, canyons. 



3. Irrigating ditches and artificial ponds. 



4. Few and relatively small marshy tracts along the 



streams or ditches or about the ponds. 



5. Rocky buttes and ridges rising above the general level. 



