TABLE III. 



SPIRIFERS, OUTHIS, AND STKOPIIODONTA, FROM THE SHELL-BEDS OF TIIE IOWA AND CEDAR RIVERS, BELONGING 



TO THE DEVONIAN PERIOD. 



All the Spirifers but figs. 5 and 7, from this formation, seem to be destitute of ril>s on the mesial fold or bourrelef. 



Tab. Ill,, Fig. 1. Spirifer Imuensis (N. S.) Iowa River. 



" Fig. 2. Cast of Sjiirifcr eurutdnes (N. S.), Pine Creek, Iowa, showing the broad area of the ventral valve. 



a. Front view of same, showing the deep broad sinus of the ventral valve. 

 " Fig. .3. Spirifer pcnnatus (N. S.), Iqwa River. , • •■ 



" Fig. 4. Spirifer ligiis (N. S.), New Buffalo, Iowa. " ' • ■, - 



" Fig. .5. SjUi)7yb- CerfaroiSi's (N. S.), two and a half miles below Roekinghani. ■ . , ' , 



Fig. 0. Spirifer eundeines, Pine Creek, Iowa. 

 " Fig. 7. iS|OJ>!/«- (N. S. ?), allied to S. iindiferous, Davenport, Iowa. ' ' v~ 



" Fig, S, 8j)irifer pennatits ? a young individual, Iowa River, 



" Fig, 9, Spirifer (undet.), in limestones of the age of the Hamilton Gro\ip of New York, near Rockingham, Iowa. 



This small Spirifer is allied to Spirifer inurcdis of Verneuil, but is smaller; cardinal angles not so 

 much produced; cardinal border less wide and vertical ; the ribs fewer, only about ten, and finely 

 imbricated by layers of increase. 

 " Fig, 10, Orthis lenlifonnis/ Near New Buffalo, Iowa, 



In size and general contour this Orthis resembles 0. lentifurmis of the Corniferous Limestone of 

 New York, fig. 4, No, 28, of Hall's New York Report, The striic are so fine as hardly to be 

 discerned without a magnifier; and the sinus of the dorsal valve is almost obsolete, 

 " Fig, 11, Strophndonia ^ ivslata, (N. i^.) Davenport, Iowa. 



