Silurian Land Plants from Ohio. — Foerste. 139 
of the scars. But from the present standpoint of paleontolog- 
ical investigation, based upon the material so far collected, 
Glyptodendron is a cephalopod and not a plant. Its surface 
features are closely those of a known cephalopod and do not 
bear the same close resemblance to any known plant. 
The result of these comparisons has been the conclusion 
that all of these specimens are congeneric. Are they of the 
same species? This the writer would not like to answer defi- 
nitely. He has no doubt that the Brown specimens so far in- 
dicate but one species. The Huffman specimen seems to have 
decidedly larger scars, and this and the absence of marked 
dorsal flattening and a more rapid increase in the diameter of 
the shell towards the aperture may constitute the distinguish- 
ing characteristics of a second species. The Eaton specimen 
scars are not sufficiently larger to warrant the creation of a 
third species. In that case the already published name for 
the Eaton specimen will have to serve also for the much bet- 
ter preserved Huffman specimen. The name Glyptodendron 
may be retained as a subgeneric term under Cyrtoceras.* 
The general curvature of the shell is now believed to be 
much nearer that of the general forms of Cyrtoceras than 
of Gyroceras. 
The classification of these shells will then be as follows : 
Genus CYRTOCERAS. 
Sub-genus Glyptodendron, Cla} r pole. 
C. (G. ) eatonense (Claypole) Foerste. . 
Localities: Near Eaton, Ohio ; also at Huffman's quarry, 
in white, very fine-grained limestone, coming from the bottom 
of thequariy. Clinton group. The Huffman specimen should 
be taken for the present as the new type of the species, since 
it alone furnishes an idea of the interior structure, general 
form, and the minuter surface details. 
C. (G.) subcompressum Beecher. 
Locality : Brown's quarry, two miles west of New ( arlisle 
*If the author of Glyptodendron may be allowed, as one of the Editors 
of the American Geologist, to intrude with a short foot note, he would 
like to suggest that, if his genus of 1877 prove to be really a cephalopod, 
its name should be entirely dropped. Etymological reasons alone would 
dictate this course, if no others existed. The subscriber has followed 
Mr. Foerste's investigation with interest for some time past, and cannot 
but feel con\ynced that he has made out a good case against the exist- 
ence of land plants in Ohio in the Clinton age, though the superficial 
markings are unusual or even unexampled in a cephalopod. — E. W. C. 
