1890.) Proceedings of Scientific Societies. 211 
phism as to be incapable of identification. The two main points which 
it is desired to illustrate are: I. The similarity of effects produced in 
the same original material by the contact action of eruptive rocks and 
by orographic disturbance. ; e power of orographic forces 
(regional metamorphism) to produce the same product from rocks 
originally the most diverse in origin and structure, Illustrated by maps, 
diagrams, and specimens, both macroscopic and microscopic. 
NOTE ON THE SYRACUSE SERPENTINE. George H. Williams, Balti- 
more, Md.—Additional and recently secured evidence of the eruptive 
nature of this rock, which is interesting as being the only representa- 
tive of its class known in the undisturbed strata of New York. 
THE SANDSTONE DIKES OF THE FORKS OF COTTONWOOD CREEK IN 
TEHAMA AND SHASTA COUNTIES, CALIFORNIA, J. S. Dilier, Washing- 
ton, D. C.—The distribution of the dikes was shown by a map, 
their mode of occurrence described and illustrated by lantern slides ; 
their mineralogical composition, microscopical structure, and chemical 
composition discussed and compared with that of the mesozoic sand- 
stones with which they are associated ; and a theory of the origin of 
the dikes proposed and discussed 
ON THE RELATION BETWEEN THE MINERAL COMPOSITION AND THE 
GEOLOGICAL OCCURRENCE OF THE IGNEOUS Rocks aT ELECTRIC PEAK 
AND SEPULCHRE MT., YELLOWSTONE NATIONAL Park. Jos. P. Iddings, 
Washington, D. C.—An occurrence of intrusive rocks and contempo- 
raneous extravasated rocks having similar chemical composition and 
different mineral composition and structure. 
ON OROGRAPHIC MOVEMENTS IN THE Rocky MouNTAINS REGION. 
S. F. Emmons, Washington, D. C.—After giving a brief abstract of 
the views which have hitherto been put forward in regard to orographic 
movements in the Rocky Mountains region, the writer proceeds to give 
his present views, founded on observations made in the field during 
the past ten years, which partially modify the views already held, and 
add to the list of movements two important and widespread move- 
ments, which hitherto have not been generally recognized. These 
occurred, the one during the Carboniferous, the other during Jurassic 
times. Evidence of the former is found beyond the boundaries of 
Colorado in Wyoming at the North and New Mexico on the South. 
The latter was even more widely felt and may have affected the greater 
part of the continent. Although the data are extremely imperfect, the 
writer has thought it advisable to present the facts which he has at his 
command, believing that when the attention of geologists is called to 
Am. N 
