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- 

 ciendy prolonged search in the limestones and shales of this series in 

 Ohio, which is nearly 25 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 Produc- 

 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, 

 Pleurotomaria chesterensis ? Holopea ncwtonensisl Naulilus specta- 

 bilus, Ctenodonia? sp. Allorisma andrewsi. (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 faunae. A cup coral, 

 Lophophyllum sp ? (See Plate XIII, Fig. 17), also occurs rarely. 

 In this connection may be described 



Mautilus if) hisidcatits. 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 



