MOVEMENTS OF THE PAETEES. 35 



thorough topographical and geological study of the country. When the 

 region of the southern part of the Hills had been worked up as com- 

 pletely as was practicable the entire expedition moved northward and 

 established a second camp on Eapid Creek below the forks, from which the 

 region on each side was in a similar manner explored ; a third camp was 

 made on Bear Butte Creek near Terry Peak, and a fourth on Inyan Kara 

 Creek about ten miles southeast of Inyan Kara. From this last point the 

 Bear Lodge range was examined by Mr. Jenney's party while the other 

 party descended the Belle Fourche to the mouth of Bear Butte Creek, 

 where all portions of the expedition again met. The main body of the 

 escort then skirted the Hills on the east side to Eapid Creek, while Mr. 

 Jenney's party crossed southeastward outside of the foothills to the mouth 

 of Rapid Creek, and the topographical party descended the Belle Fourche 

 and ascended the South Fork of the Cheyenne to the mouth of Rapid Creek, 

 where all parts of the expedition met September 22, preparatory to the 

 homeward march. 



The details of the methods pursued in the work of exploring the Hills 

 can be of no interest in this place. The results of the geological studies, of 

 the examination of the mineral products, and of the astronomical work are 

 given with considerable detail in the several chapters referring to those 

 subjects and in the accompanying maps. 



The country on the east side of the Hills has much the same character 

 as that on the west. Near the Hills is a succession of ridges of the upturned 

 and eroded Cretaceous rocks, which decrease in inclination and size as their 

 distance from the Hills increases, till near the borders of the Cheyenne the 

 country has a flat mesa-like appearance, cut up, however, by numerous dry 

 ravines. 



South of Rapid Creek, two or three miles from its mouth, and occupying 

 the divides between Rapid, Spring, and French Creeks, are irregular areas 

 of the lower members of the White River Tertiary, attaining a maximum 

 thickness of about 200 feet. They possess all the lithological characteristics 

 of the White River group, but no organic remains were found, even after very 

 careful examinations. No perceptible unconformity of dip could be detected 

 between the underlying Cretaceous and these Tertiary strata, but in the 



