SCIENTIFIC EXPEDITION TO NORTHEASTERN COLORADO 1 65 



siderably extended by these collections. From the specimens at hand 

 a general idea of the flora can be obtained and further collections can 

 be intelligently undertaken. As the specimens were all gathered about 

 the last of June it is desirable that future and more complete collections 

 be made later in the season. 



EXPLANATION OF PLATES 

 PLATE I 



Fig. I. — Bluffs at southern edge of high plains east of Grover, Weld Co., Colo. 

 These bluffs consist of sandstones and clays belonging to the Loup Fork and White 

 River beds. They contain numerous vertebrate remains. The illustration shows how 

 portions of the bluffs may be cut off as isolated buttes. The region in the foreground 

 belongs to the eroded area of the South Platte River valley. 



Fig. 2. — View on the high plains to the north of the bluffs shown above. Note the 

 very flat character of the country with its sparse vegetation of coarse composites and 

 bunch grass. 



Fig. 3. — River-bottom forest on the bank of the Cache la Poudre River near Windsor, 

 Colo. The forest varies from fifty to a few hundred feet in width. The trees are chiefly 

 cottonwoods and willows. 



PLATE II 



Fig. I. — Nesting-site of cHff swallows at Chalk Bluffs in Weld Co., Colo., near 

 Cheyenne, Wyo. In these bluffs no fossils were found by the expedition. 



Fig. 2. — Cottonwood trees on Crow Creek with herons' nests in the upper branches. 

 Note the stunted character of the trees. Along many of the creeks there are just such 

 narrow lines of trees forming no true river-bottom forests. 



