SUN DANCE HILLS. 197 



No fossils were discovered in these beds, but, with the exception of the 

 red clays at the base, they are supposed to belong to the Jura. It is 

 probable that they are upturned on all sides so as completely to encircle 

 the uplift, but they are concealed by debris. 



A short distance from the base of the butte no evidence can be seen 

 of the close proximity of an igneous peak. 



From this brief description it will appear that Bear Bntte is an igneous 

 extrusion, producing no dislocation or metamorphism in the strata through 

 which it was protruded, except at its very base. It gives no indication that 

 its igneous material ever overflowed as a true lava, but rather that, like the 

 other peaks of this region, it was a huge viscid bubble, breaking through a 

 great thickness of superincumbent strata. 



Sun Dance Hills. — These two hills are in the northeastern bend of the 

 great Red Valley, about eight miles southeast from Warren Peaks and 

 twelve miles due north from Inyan Kara. They are the simplest and best 

 illustrations of the pustular nature of the igneous ejections of the Black 

 Hills. They are about three miles apart and are not very prominent except 

 in the local topography. The higher of the two is 1, 1 0t) feet above the 

 surrounding valley, while the eastern and smaller hill is, by estimation, not 

 over 600 feet above its base. The rock is very similar to that of Bear Butte 

 and Inyan Kara, a hard, gray, compact trachyte. The larger hill was 

 ascended and found to have a ridge-like summit with its major axis pointing 

 in a northwesterly direction. Around the bases no more recent strata were 

 recognized than the red clavs and limestone of the Red Beds, and these are 

 but little disturbed. The limestone surrounds each in a gentle slope very 

 like the broken edges of a piece of paper that has been punctured by a 

 sharp pencil but it is in nowise shattered. It seems to conform to the 

 little irregularities of the uplift almost like a flexible material. 



Inyan Kara is the most prominent peak on the west side of the Hills. 

 It is situated in the Red Valley, west of the limestone plateau. Its name 

 first appears on the map of Lieutenant Warren, and as translated for him 

 signifies "the peak which makes stone." Inyan signifies in the Dakota 

 tongue "stone," but the word Kara is unknown in the language, and is 

 probably a corruption of Ka-ga, "to make" The summit of the peak is 



