20 
BULLETIN OF THE LABORATORIES 
Flint Ridge is in the relative abundance of the species. Naticopsis 
nodosa has not been recognized from the Flint Ridge shales and Pro- 
ductus semireticulatus is abundant in the Waverly, but rare in the 
Flint Ridge shales. It is possible, but not probable, that the two ho- 
rizons are identical. The sandstone and shales underlying this band 
are unfossiliferous and the next link in the series connecting the coal- 
measures and the Waverly is found in the so-called Maxville or Chester 
limestone. A considerable fauna will yet be restored to us by a suffi- 
ciently prolonged search in the limestones and shales of this series in 
Ohio, which is nearly 2^ feet thick in the vicinity of Fultonham. 
Eleven species have been described from this horizon by Whitfield. 
The characteristic species which are everywhere abundant are Prodiic- 
tus parvus, which, however, is often much larger than the type and 
approaches P. semireticulatus in some characters, Spirifer glaber, 
Athyris subtilita, Euomphalus planodorsatus and Bellerophon sp. 
PkiLrotomaria chesterensis ? Holopea neivioncnsis 2 Nauliliis specta- 
bilus, Ctenodonta 2 sp. Allorisma andreivsi. (Plate XIII, Fig. 12) and 
Spirifer incrcbescens, H. With regard to the last mentioned species 
it may be here noted that no difficulty exists in tracing this species to 
its successor in the coal-measures (S. opirr.us) and to its probable pro- 
genitor in the St. Louis group (S. Keokuk var. Hall), this in turn to 
the Keokuk group. There are many hints of this sort which will oc- 
cur to the attentive student of these successive faunre. A cup coral, 
Lophophyllum sp ? (See Plate XHI, Fig. 17), also occurs rarely. 
In this connection may be described 
Jfautilus (?) hisulcatus . sp. n. 
(Plate XI, Fig. 16.) 
Shell of moderate size, very compressed rotate, volutions not em- 
bracing, (two to three?) transverse diameter of outer volution less than 
one-half the dorso-ventral diameter, transverse diameter greatest one- 
third from the ventral side ; upper and lower surfaces marked dorsally 
by a Carina within which is a broad, shallow grove, followed by a sec- 
ond ridge about one-third from the dorsal margin, succeeded by a 
groove shallower than the first, which is followed by a gently convex 
portion extending to one-fifth from the ventral margin, where is a slight 
Carina, beyond which the surface inclines to meet the similar plane of 
