RESTORATIONS OF CERTAIN: DEVONIAN CEPHALO- 
PODS WITH DESCRIPTIONS OF NEW SPECIES* 
A cephalopod fauna remarkable for the form of some of its species 
as well as for the abundance of individuals occurs in the hydraulic 
limestone of Middle Devonian age near Milwaukee, Wis. The 
specimens are crushed to such an extent by pressure applied at var- 
ious angles with reference to the vertical axis, that a hasty study 
would probably result in their separation into a large number of 
species and perhaps genera. In fact, early collectors were led to 
believe that at least twenty species were represented, whereas, all 
should probably be included in nine or ten species. 
In order that these distorted forms might be clearly understood, 
and to reduce as much as possible the lability to error in their deter- 
mination, restorations in clay and later in plaster were made from 
careful measurements of actual specimens. In these restorations it 
was found necessary to restore the apex without reference to the 
fossils, since in no specimen was that portion of the shell preserved in 
its entirety. For example, in Gomphoceras calvini the lower one and 
one-quarter inches of the restoration is hypothetical, although in 
G. wisconsinense practically the whole specimen is known. The 
transverse section was made circular in the restorations of all the 
species. In the case of G. wisconsinense this was doubtless the true 
shape, but it is possible that in two of the restorations (G. whitfeldt 
and G. fusiforme) the cross-section was elliptical. 
The rim of the aperture of G. wisconsinense, G. calvini, and G. 
jusiforme is pretty well known, but in G. whztfieldi its exact contour is 
in doubt. It is difficult in all cases to determine the position, if any, 
of the hyponomic sinus. 
It should be remembered that the restorations in this paper are 
in every case of the interior. If a restoration were made of the exte- 
rior, account must necessarily be taken of the thickening of that por- 
tion of the shell forming the chamber of habitation. In none of our 
t Published by permission of the Director of the Wisconsin Natural History 
Survey. The writer is indebted to Dr. R. Ruedemann for suggestions and criticisms. 
459 
