24 TJa American Geologist. Jan. isoi 
Its outcrop in Kansas is mostly linear and very irregular. Be- 
ginning on northern tributaries of the Medicine Lodge river in 
the northwestern part of Barber count}-, it extends up the valley 
<>f that river to points on the headwaters a few miles north and 
west of Belvidere ; thence to the west, in an irregular southeast- 
erly directed loop, to a point in the bed of Bluff creek. Clark 
county, a few miles above Yanhem : and thence southwest to a 
point on Crooked creek, Meade count}-, near Odee. West of 
these points, it passes beneath the upland. It reappears in the 
Public Land between the Cimarron and the North Fork of the 
Canadian in the region where these streams most closely approach 
each other. This and some limited occurrences in the divide be- 
tween the Bed Fork and the Cimarron, south of Avilla. connect 
it with the Canadian and Washita river district in which it was 
first recognized in its true relations in 1853 by Prof. Marcou. 
Of the two divisions into which the American Neocomian can 
be more or less distinctly separated in Texas, only the older, the 
Fredericksburg of Prof. Hill, is present in Kansas. The actual 
contact of the Dakota series upon the Fredericksburg division is 
well shown near the heads of Bear creek and the Little Sandy, in 
Clark county, and of the Medicine Lodge river and several of its 
branches in Kiowa county ; the latter district locally yielding 
characteristic Dakota leaves in abundance. It is less perfectly 
shown by the contact of remnants of a Dakota ledge entombed in 
Loup Fork calcareous sandstone at the point where the trail from 
Dodge City to Camp Supply descends from the divide north of 
Ashland. At the Blue Cut hill. S. S. W. of Belvidere. in Kiowa 
county, and on mam- high points in this and neighboring counties, 
boulder-remnants of the Dakota sandstone overlie the Fredericks- 
burg shales and usually bear incrustations which unmistakably indi- 
cate their release from the Loup Fork calcareous sandstone. We 
have thus clear evidence of the former deposition of Dakota 
sediments upon those of Fredericksburg age over this region and 
of their subsequent removal from most of it by erosion. At the 
West Bear creek locality, in Clark county the superimposed Da- 
kota shows a thickness of not less than fifty feet ; on the Middle 
Branch of the Medicine Lodge, it has a thickness of not less than 
-<\ enty. 
The thickness of the Neocomian series in Kansas is variable. 
but probabl}' nowhere exceeds 150 feet. This maximum is ap- 
