OF DENISON UNIVERSITY. 3 1 



Crania hamiltoniae , H. (?) 

 (Plate XII, .Fig. 10.) 



This little species is found adhering to mollusks and brachiopod 

 shells and is largely modified by the ornamentation of its host. Our 

 specimen agrees as fully as might be expected with the smaller varie- 

 ties of the species quoted. 



Broadly oval or sub-circular ; dorsal valve sub-conical ; apex sub- 

 central or excentric, pointed, surface marked by very fine (scarcely 

 lamellose) striae. Lower valve not seen. Concretionary layers at 

 Moot's run — lowest fossiliferous horizon. 



This species, whether specifically identical with C. hamihonix- or 

 not, has a decided Devonian aspect. 



Productus JVebrasceiisis, (?) 

 (Plates I, Fig. 24; III, 23(?) 23a.) 



Specimens having the characters of this species are widely distril>- 

 uted. Though never attaining a very large size there is a considera- 

 ble range of variation in this respect as well as in outline and form. 

 The rather regular and prominent pustules are sufficiently characteris- 

 tic. The species is known from the horizon of congl. I, to the top, but 

 may descend lower. 



Product as snn Ireticulatus. 

 (Plates I, Fig. 26; III, 24; \TI, Fig. 11 : X, 6, 6a.) 



This widely distributed species is especially chara( leristic of the 

 uppermost Waverly, as found at the tank north of Newark and in the 

 freestone. The species attains a large size and may be recognized by 

 the great prominence of the ventral valve near the strongly incurved 

 beak. 



J^rodurfas arcuatiis. "•»"• 

 (Plate III, Fig. 18.) 



Prof. Hall's descrijnion runs as follows : 



"Ventral valve much elevated, longer than wide, very gibbous. 



