586 



NEW SPECIES OF BEACH 10 TOD A. 



SPIRIFER ETJRUTEINES. 

 (Tab. III., figs. 2, 2 a, 6, and G a.) 



Specific character. — Shell nearly semi-elliptical ; cardinal area very wide, slightly concave and finely 

 striated ; narrow perforation ; beaks sometimes more than half an inch apart, smooth, with eighteen to 

 twenty ribs on either side of the bourrelet, finely striated longitudinally, sometimes studded with small 

 granulas, bourrelet rather narrow, with a shallow sinus in the median line, finely striated, and crossed by 

 fine concentric lines of growth, and sometimes by fine granulse. Sinus of the dorsal valve, also some- 

 times finely granulated. Length, one inch, breadth one and a half inches. 



This is one of the most common species of Spirifers in the limestones of the Red Cedar and Iowa 

 Valleys, as well as the hydraulic limestone near the Falls of the Ohio. It was figured in the Report of 

 1839, but without any detailed description. 



SPIRIFER CEDARENSIS. (N. S.) 

 (Tab. III., fig. 5.) 



Specific character. — This Spirifer is much deeper from the beak to the circumference than either of 

 the preceding, and, though very acute at the angles, it is much less produced along the hinge line. It 

 differs, moreover, in the sulcus having small, longitudinal ribs. On either side of the mesial fold there 

 are from twenty-three to twenty-five ribs; those on the angle are so fine that it is difficult to count them 

 with precision. Shell considerably gibbous, especially towards the umbo. A few concentric wrinkles 

 near the angles and border. From the limestones of Cedar Valley, two and a half miles below Rocking- 

 ham, Iowa, of the age of the Hamilton Group of New York. 



SPIRIFER INEQUICOSTATIS. (N. S.) 

 (Tab. V., fig. 0.) 



In general shape this fossil resembles S. semicircidaris, it differs, however, from that Spirifer, as well 

 as from the bisidcatus, which De Koninck gives as a synonym, in several essentials, which appear to 

 indicate a distinct species. 



The ribs, though simple, are very unequal in size, some being exceedingly fine, others coarse ; no 

 distinct sulcus on the mesial fold other than the simple grooves between the ribs ; the mesial fold or 

 bourrelet is sharper and more divergent, by which it is much narrower near the beak. 



Phillips does not give the number of ribs either on the mesial fold or general surface. This species has 

 nine ribs on the mesial fold, and seventeen on either side of it, which is nearly the same as on the bisid- 

 catus, according to De Koninck. 



Dimensions. — -f 0 long, 1 T 3 ^ wide. Locality, carboniferous limestone of Iowa. 



FORAMINIFERA. 

 SELENOIDES. (N. Gr. ?) 



Generic character. — It was supposed at first that this singular fossil from limestones of Lower Silurian 

 date, F. 3, a (and bl), of Iowa, would fall into the genus Orbitulina. But as D'Orbigny regards this 

 genus as unequal-sided Orbitolites, in which one side is convex, incrusted, and having concentric lines; 

 the other concave, not incrusted, and showing numerous cells in oblique lines around the sides ; it can 

 hardly be grouped with it, as the Iowa fossil is umbilicated on one side, and the cellular, ring-shaped 

 surface, instead of being concave, is so convex as to form nearly a coiled cylinder. The other side being 

 partly defaced in splitting it out of the rock, it is difficult to say whether it had a cellular surface similar 

 to that shown on fig. 13, Tab. II. b, or concentric lines; what portion of it is visible rather indicates that 

 the fossil was unequal-sided, not being umbilicated on the other surface ; probably cellular, and not with 

 concentric lines. There are no cup-shaped cells opening round the periphery, as in Orbitolites, which are 

 said to be equal-sided Orbitulinas. 



For the above reasons, I think it will constitute a new genus, peculiar to the Lower Protozoic rocks. 

 The horizontal section seems to present an internal arrangement of cells similar to those of Orbitoides. 



