528 PRO( BEDINGS OF NEW YORK MEETING. 



briefly as follows : In the region now bordering the Gulf of Mexico on the south and 

 • during the first half of the Cretaceous age marine conditions prevailed, and in tin- 

 sea of that time and place several thousand feet of limestone were deposited — the 

 Comanche group of R. T. Hill and Dr. White ■ Most of our continent was out of 

 water during the long interval asured by the deposition of the Comanche lime- 

 stones, but about tin- middle of the Cretaceous age the sea rose over its shores and 

 submerged all 1 1 1 « - great depressed area between the Alleghany and Canadian high- 

 land- on the east and the Rocky Mountain- and Wasatch on the west. When the sea 

 invaded this area it- shore wave- spread a sheet of sea beach, the Dakota sandstone 

 serie-. as far a- the submergence extended. A- the water deepened over the area of 

 the plains, marine sediments were laid down on the Dakota ; in the open sea, lime* 



2 i feel or more thick — the Fort Benton, Niobrara, Fort Pierre, and V<>\ Hills 



groups of Meek and Hay den. Near the western shore of the Cretaceous sea the sedi- 

 ment- were more earthy, shales alternating with concretions and continuous beds of 

 limestone, and in places 2,000 feet or more of bituminous -hale. In the mountains of 

 New Mexico, Colorado, and Wyoming the divisions of Meek and Hayden's upper 

 Missouri -ection cannot be identified, and so Mr. Clarence King called the strata 

 immediately above the Dakota the Colorado group. At the top of this we find a 



sudden change of sediments, sandstone and .-hale- with beds of coal suc< ding the 



bituminous shales and lime-tones. This is the Laramie. There is no unconform- 

 ity here except what may be due to erosion and such as we always or often lind 

 where strata of coarse material-, sandstones and conglomerates that have heen 

 deposited by rapid current-, rest upon fine ami quiet-water sediments. The Laramie 



is tied to the Fox Hills by BOme of its fossils, and the heavy sand-ton- which lies at 



its base in southern Colorado and New Mexico has heen called by Professor Stevenson 

 the Fox Hills sandstone, but it seem- to me better to begin the Laramie with the 

 change of sediments rather than attempt to maintain the identity of the Fox Hill- 

 group in this region. The epoch of the Laramie was one of disturbance, at least of 

 local oscillation of water level. The sandstones are shore deposits, the -hale- -hallow 

 water sediments, and the numerous coal beds were formed under BUbaerial condition-, 

 and they are remarkably local. Sections quite near each other show great differences 

 in the number, relative position, and thickness of the coal -earn-. This means frequent 

 and local changes of level. The coal seams give the Laramie group greater economic 

 importance than any other formation in the middle and western parts <>i' the continent. 

 It i- generally coal-bearing, and it- coals are in some places of remarkable thick' 

 and purity. Probably no equal area in the world rival-, in the quantity and quality 

 of it- coal, portion- of the Laramie of western < 'olorado. 



Mr. .1. B. Tybrkll: We find what we have called the Laramie and have corre- 

 lated with the Fort Union group, lying directly on the Pox Hill- beds', the bed.- from 

 which the plants are largely obtained. I have collected large number- of them my- 

 -.■If. Between those plant bed- and the typical Fox Hills bed- there is a series, lying 

 perfectly conformable to both, of white -and- and days that hold the most of our 

 western coal deposits, and which have been discriminated in the reports of the Geo- 

 logical Survey of Canada. The three -ere- in Canada an- perfectly conformable. 

 There i- no break whatever between the Colorado group and the top of the Laramie, 



and tlnre i- a thickne-- of live tosix thoii-and feet to tin- top of the Fort Union group 



with no break at all in -upetpo-ith.n ; there ha- 1 n a regular Bequence from the 



bottom to the top. So if tic Laramie oomea in anywhere it mu-t conn- in at the 

 bottom, and it app'-ar- to me that it mu-l uome in there and not in tin- upper bed.-. 



