356 The American Geologist. June, i89o 
septa are shown. These vary from 4 to 10 in the space of an 
inch. The siphuncle is central. Many specimens retain the 
nacreous exterior. A few show the body chamber, and one or 
two of these are very similar to Evdoccras 'protciforme var. 
strangulatum as figured b}" professor Hall. It is a question 
whether this species is not really the same as certain forms 
described as Endoceras from New York. 
Tentaculites sterling ends. Professor Hall has lately shown'' 
that forms described as Tentaculites, Ortonia, Conchicolites, 
Spirorbis, etc., are really only certain phases of development 
of Cornulifes incurvus Shumard. Whether this be so or 
not, there can be scarcely any doubt but that Tentaculites 
osivegoensis, T. sterlingensis, T. minutus, and T. richmondensis 
are all the same species. The differences are too slight to base 
species upon. 
Plunndites jamesi. A few plates of this species showing the 
characteristic double curve were found. It is interesting as ex- 
tending the range of the species from New York to the Missis- 
sippi. A single plate of a form of this genus is noted as hav- 
ing been found in the Pogonip of Nevada.^^ 
In respect to the lithologic features of the Cincinnati group 
and Maquoketa shales we have seen that they are identical. 
Professor Plall refers to the close resemblance the rocks at 
Savannah bear to those of Madison and Cincinnati, at all 
three of these localities consisting of intercalated shales and 
limestones. The same fact has been recognized b}"" other 
writers. 
Lastly the position of the shales in relation to over and 
underlying formations is identical with the Cincinnati group, 
the Trenton lying below and the Niagara above in both in- 
stances. 
With all these facts in view, namely, that the Maquoketa 
shales are the almost direct continuation of the Cincinnati 
series; that the pala^ontologic features of the two are almost 
identical ; that the lithologic features of the two are the same, 
and that the position of the two in the geological scale is the 
same, it does not seem wise to retain the name Maquoketa 
as a distinct formation. It would seem better to con- 
sider the rocks as part of the Cincinnati series, dropping the 
term Maquoketa altogether. 
■"Paleeon. of New York, vol. 5, part 2, pp. U)o-]6(j, 1879. 
='''Mon. U. S. Geol. Survey, vol. 8, p. 88, 1884. 
