322 KEMP AND KNIGHT — LEUCITE HILLS OF WYOMING 



consisting of diopside, leucite. apatite, and glass. In color it is light 

 creamj^ brown, and it is ver}' schistose from the parallel arrangement of 

 the phlogopite. It is not particularl}^ rich in leucite. 



ID DINGS BUTTE AND DIKE 



Iddings butte is a volcanic neck which forms an elliptical mass 200 

 to 300 feet long and 75 feet wide. It is located on a conical hill of 

 Laramie strata, and consists both of solid rock and agglomerate, just as 

 do the other necks. From the neck a dike bears away to the southeast 

 for about 200 feet, level with the hill. We name these two exposures 

 after Professor Joseph Paxton Iddings, of Chicago University, in recog- 

 nition of his work in Yellowstone park and Crandall basin, Wyoming. 



The rock is a dark gray orendite of a marked schistose character 

 from the abundant parallel phlogopite. Under the microscope it reveals 

 swarms of little leucites, much sanidine, considerable diopside, and a 

 great richness in phlogopite. The agglomerate is likewise a dark gray 

 rock, and consists partly of orendite and partly of fragments of sedi- 

 mentaries. 



WEED BVTTE 



This lies in the general direction of the strike of Iddings dike and is 

 another neck resting on a rounded hill at a lower elevation than the last. 

 The rock has not been examined with the microscope. We name it after 

 Mr Walter Harvey Weed, of the United States Geological Survey, in 

 recognition of his work in Yellowstone park. 



HALLOCK BUTTE 



Beyond Weed butte to the southeast is another neck rising from a 

 low hill. The rock has not been examined with the microscope. We 

 name this exposure after Professor William Hallock, of Columbia Univer- 

 sity, formerly physicist on the Yellowstone Park Survey. 



Talus Covered Hills 



endlich hill 



Northeast of Iddings butte there is a talus covered hill, where the 

 blocks of lava are very large and have the appearance of being the resi- 

 due of a former sheet or dike, but no rocks in place were discovered. 

 This hill has a diameter of about a half mile at its base and is well cov- 

 ered with the blocks. The rock has not been examined with the micro- 

 scope. We name it Endlich hill after the late Dr F. M. Endlicli, of the 



