NEW FOSSILS OF THE COENIFEROUS FORMATION BARKIS. 287 



nsl;^nce, where both concentric and radiating striae are seen on the left 

 valve, concentric striae on the right. 



Fig. 9 represents the left valve, the concentric stria; more numerous 

 and stronger on the specimen than on the figure. From bed No. 2. 



The shell figured is from the collection of Prof. Pratt. 



CEPHALOPODA. 



Gyroceras Pratti (n. sp.). 



Plate X, figs. 1 and 2. 



Shell large, composed of one and a half volutions, rapidly enlarging 

 from tlie apex. Along the side of the shell, and parallel to its volutions, 

 is a prominent angular ridge, dividing the disk into very irregular parts, 

 two-thirds of the surface inclining with a gentle curve in a dorsal, the 

 other third in a ventral direction. The dorsal inclination is gradual, the 

 ventral abrupt. 



Septa distant. At the last one of the series, where the dorso- ventral 

 diameter measures three inches, the distance of the septa on the dorsal 

 side is one inch, on the ridge (two-thirds across the disk) one-half of an 

 inch, while on the ventral side it has declined to one-quarter of an inch. 

 These measurements will hold equally good of the last ten septa. 

 Body chamber occupies nearly half of the last volution. 



In the larger specimen figured, the greatest diameter across the disk is 

 eight inches. The dorso-ventral diameter of the outer volution is four 

 inches. The transverse diameter at the same point is four inches. The 

 number of septa is about twenty, visible the entire length of shell. 



The smaller shell preserves a similar ridge on its disk, differing mainly 

 in retaining traces of ornamentation, the apex for the distance of seven 

 or eight septa being marked by a series of elevated longitudinal ridges. 

 One side of each of these shells is well preserved, the other much marred. 

 In each instance the apex is a little out of place, most probably dis- 

 torted by pressure. The figures are half the size of the fossils. 



Pig. 1 very fairly represents the original. 



Fig. 2 shows the longitudinal striae on the apex, through which can 

 be seen the septa, necessarily faintly shown. These fossils are only 

 found in bed Xo. 2. This shell is named in honor of its discoverer. Prof. 

 Pratt, the efficient Curator of the Cabinet of the Davenport Academy of 

 Natural Sciences. 



CRUSTACEA. 



Proetus Davenportensis (n. sp.). 



Plate xi, fig. 8. 



Body subelliptical, length to breadth nearly as three to two. Head and 

 thorax of equal length, pygidium somewhat shorter. Breadth of head 

 nearly twice its length. Border at posterior angles of the cheeks pro- 

 duced into long spines, extending three-fourths the length of the thorax, 



