1895.] In the Region of the new Fossil, Demoneliz. 217 
so thickly strewed about as to give the idea of their having 
formed a veritable forest. Very few other fossils are found 
with them. The celebrated fossiliferous or Bad-land forma- 
tion, is far below. 
The more perfect of these corkscrew-like fossils consist of 
an invariably perpendicular spiral, and, running away and’ 
upward from its base, a great, log-like stem. The greatest 
number of whorls that we found in a single specimen was 
thirteen, which rose to a height of more than eight feet. 
The stem of this specimen was some thirteen feet long. Some- 
times “screws” may be found without a stem, sometimes the 
_ spiral, turning either to the right or left, may be broad and 
open, at others it may be very close. Now and then a specimen 
may be found in which there is a central pole-like portion 
around which the spiral turns. More frequently there is 
found only a few whorls and a short stem. 
At a little lower level than that at which we found the 
finest specimens, very irregular and prostrate forms are com- 
mon. In the banks of the ravines they look likeso many large 
tree roots exposed by erosion. In one instance a screw with 
about three whorls was found at this lower level, which, unlike 
any other that we had seen, ended below in two roots that 
branched off from one another at a broad angle. 
These strange fossils consist of a white substance a little 
harder than the semi-petrified calcareous sandstone in which 
they occur, and, when exposed by wind or water, stand out in 
bold relief against the cliffs or walls of the ravines and “ blow 
outs.” In’some cases they project like tree stumps, and, strewn 
about among these, fragments from a few inches to several feet 
inlength are common. The surface of both spiral and stem 
may vary from fairly smooth to rough and knotty. Often 
small filaments are broken off in digging, but as sheet-like 
layers of similar hardness and appearance are frequently 
broken through, it may be doubtful whether they really 
belong to the fossil. Sometimes the knots, or even the whole 
surface, made up of innumerably fine filaments, may look like 
that of a hard and compact sponge. In the broken cross 
section an external whitish ring is presented, surrounding a 
