■420 Systematic Paleoxtology 



Spirifee gordoni n. sp. 

 Plate LXXII, Figs. 5-7 



Description. — When the finer surface detail is preserved, this species is 

 readily distinguished from all other Oriskany spirifers except S. con- 

 dnnoideus by its exceedingly line radial stri«. However, the Oriskany 

 fossils rarely preserve the finer detail and for this reason it is not so easy 

 to recognize this species. In general 5'. gordoni will be confused with 

 S. intermedins, but it is distinguished by the rounded cardinal angles, 

 making the species far less alate than S. intermedins ; moreover, the fold 

 is more depressed and the sinus has a flat central area. The latter char- 

 acter, as a rule, will alone distinguish this form from all other Cumber- 

 land species. S. gordoni differs from S. perdewi in being a more depressed 

 or thinner and more transverse species. 



Length 3.5 cm. ; width 4.4 cm. 



Occurrence. — Oriskany Formation, Eidgely Member. Knobly 

 Mountain near Cumberland. 



Collections. — Maryland Geological Survey, U. S. National [Museum. 



Genus RETICULARIA McCoy 



Reticularia bicostata ( Vauuxem) 



Plate LXXII, Figs. 8-10 



Orthis Mcostatus Vanuxem, 1842, Geol. N. Y., Third Dist, pp. 91-94. 

 Spirifer Mcostatus Hall, 1852, Nat. Hist. N. Y., Pal., vol. ii, p. 263, pi. liv, flg. 4. 

 Spirifera bicostata Hall, 1883, 2d Ann. Rept. N. Y. State Geol., pi. Ixi, flg. 7. 

 Spirifer Mcostatus Hall and Clarke, 1893, Pal. N. Y., Tol. viii, pt. ii, pp. 19, 

 37, pi. xxxvi, fig. 7. 



Description. — " Somewhat ovate triangular, the dorsal valve gibbous, 

 with the beak extended and incurved over a short triangular area ; ventral 

 valve convex; surface marked by conspicuous concentric subimbricating 

 striae; dorsal valve with a distinct plication on each side of the sinus, and 

 toward the base are two other obscure plications on each side, presenting 

 three and sometimes four gentle undulations on the margin on each side of 

 the center; cardinal line shorter than the width of the shell, and the area 

 scarcely extending so far as the cardinal line; extremities distinctly 

 rounded." Hall, 1852. 



