380 The Americcm Geologist. December, 1895 
lIclTs llali' Acre on Elk creek in ("onuuiclie count}'. TJie ter- 
rane consists of a bed of black carbonaceous clay-shale fifteen 
or twenty feet thick, resting upon tlie Clianipion shell-bed and 
characterized by a peculiar method of disintegration, breaking 
down under the weather into small, tiat aiul thin, sharp-edged 
spalls resembling wafers, a peculiarity tliat iuts suggested for 
this shale the name of Wafer-sJuile. 
The Black Hill shale is for the most ])art barren of well- 
preserved fossils. In places it has in its upper part a bed of 
ill-shapen GrupJuva^ some of the examples of which evidently 
are deformed G. i-oamer/', while some others possibly should be 
considered as representing (r. hilli, together with O.stnut sub- 
orafa and Exogyva fexaiia. Elsewhere its upper portion yields 
crushed or entire shells and casts of Modiola (•oiiceiifrirc-coH- 
fcllata? [M. .stoiieirnJ/eiisi.s), 7\i/k's /tc/r/t/cfciis/.s^ reptilian 
hones (Flesiocheli/s be/riflereiiisi.s) nnd other fossils, most of 
which are abundant and often linely preserved in the some- 
what higher zone that is transitional from the Wafer-shale to 
the upper subdivision of the Fullington shales, viz.: 
'THE BLUE CUT SHALES. 
These are named from "the Blue cut," a deep railway-cut a 
few miles south-southwest of Belvidere, the same from wliich 
the writer's Blue Cut section was named. .The Blue cut, how- 
ever, in the first instance, owes to the color of these shales the 
name by which it is known to the railway employees and in- 
habitants of the Belvidere district. They consist of alterna- 
tions of blue-back and gray argillaceous shales with minor 
beds of sandy shale, ferruginous sandstone and shell limestone. 
In the latter the shells ditfer from those of the Champion 
shell-bed in character of preservation and in color, the shells 
of the Champion shell-bed being largely calcite and gray in 
color, while those of the Blue Cut shell-beds (except the gray 
to gloss}^ purple-red Ontreldoi and the sometimes blackish 
Xevitida') nearl}'' all consist of ferruginous yellow limestone. 
The transitional Black Hill-Bliie Cut horizon, in certain local- 
ities, yields the smaller and generally rarer shells more abun- 
dantly than other horizons. In the thicker shell-beds, a little 
above the base of the terrane, (J upriiueria 1e.r(iii<( var. h'loirdna 
is conspicuous on account of its size as well as its abundance, 
some of the beds having tlieir mnjor i)ortion built u]) of these 
