32 The American Geologist. Jan. 1891 
The occurrence here of two strata lithologicalty and pal&ontol- 
ogically like Belvidere 5, one basal, the other median in the series, 
and the association of the latter with a sandstone not unlike the 
Cheyenne, gives some color to the supposition that whatever he 
its palaeontologic relation to the upper Jurassic, the Cheyenne 
sandstone should at least be considered stratigraphically a mem- 
ber of the lower Cretaceous. Indeed, at the point of disappear- 
ance of the Cheyenne stratum near the Blue Cut, may be seen in- 
dications of a change in the character of the stratum, as if it 
were a premonition of a giving place of the sandstone to shale, 
by which latter the sandstone is at other places more or less in- 
vaded. 
Of the count}' of Comanche, the Xeocomian series is best de- 
veloped in the northeastern part, where it resembles that of the 
adjoining part of Kiowa county, both lithologically and in the 
abundance of Cyprimeria crassa, Thtrritella, and associate fossils 
of the Belvidere Section. The horizon of the small Grypluc" 
combining features of G. pitch' ri with those of G. arcuata (No. 5 
Belvidere Section), also appears here between the Cheyenne 
sandstone and the black shale ; but the fossils are often poorly 
preserved, b} - reason of the excess of sulphur, iron, and gypsum. 
The black hill south of Avilla. which I have crossed, I have never 
found time to examine ; but I have casually observed Gryphcea 
pttckeri, Ostrea franhlini, Cyprvmeria crassa, etc., as among its 
fossils. The wide separation of this hill from other outcrops, and 
the numerous loose specimens of Gryphcea scattered about to the 
west and to the northeast of Avilla, taken in connection with the 
outcrops on Elk and Mule creeks, testify to the former existence 
of the Neocomian series over the entire county, and to its subse- 
quent extensive erosion. 
Loose Gn/j>/ucd and Exogijnt also occur in the western parts of 
Harper and Kingman counties. 
It was, till recently, supposed that the Neocomian formation did 
not occur north of, nor indeed quite to, the Arkansas river. In 
my " Geological Notes on the Region South of the Great Bend 
of the Arkansas," {Bui. 9, p. 37, Feb. 1889) I announced the 
discovery of a supposed Comanche outcrop on the west line of 
McPherson county. This locality has been insufficiently exam- 
ined, but is characterized by yellow to blue-gray shales with layers 
of Ostrea franhlini breccia and other stony layers in which Car- 
