ORISKANY SANDSTONE. 4iff 



more faintly defined, extending downwards and terminating in a lanceo- 

 late point. The ovarian spaces are corrugated or pustulose, and the lower 

 part of the vascular area is striato-punctate or striato-pustulose ; the 

 impressions of the external striae appearing more conspicuously than in 

 either of the preceding species, while the impressions of the ramifying 

 vessels are usually but faintly marked or not at all shown. 



This species is remarkable for the large size to which it sometimes attains. One 

 of the individuals figured 'has a width of four, with a length of a httle more than 

 three and a half inches; while the other has a width of a little more than three and 

 a half, with a length of three inches, being perhaps the largest brachiopod known 



in the rocks of this State. 



PLATE XCIII. 



Fig. 4. The cast of a ventral valve, preserving the marks of the muscular impression and 

 the imprints of the radiating striae. 



PLATK XCV. 



Fig. 8. A east of the ventral valve, showing the muscular impression in part, with the shell 

 preserved upon the lower part of the specimen. 



PLATE XCIV. 



Fig. 2 a. The impression of the dorsal valve of this species in sandstone. The cavities of the 

 cardinal process are not shown in the figure. 



Fig. 2 6. A cast taken from a similar mould, showing the diverging divisions of the cardinal 

 process, crenulated hinge-line, muscular impressions, etc. { The details of the 

 marking are not well shown in this figure.) 



Fig. 2 f , d. The impressions of the same in sandstone, the marking being preserved in dif- 

 ferent degrees of perfection in the two specimens. 



Geological position and localities. In the Oriskany sandstone : Albany and Scho- 

 harie counties ( NeW-York), and Cumberland ( Maryland ). 



Sti'opliodoiita liiickKiBiii. 



Plate XCIII. Fig. 2 & 3 a, i. 

 Strophodonta lincklttni : Hall, Regents' Report, 1857, p. 55; Palaeozoic Fossils, 1857, p. 15. 

 Shell semielliptical, more than three-fourths as long as broad ; lateral 

 margins usually contracted below the extremities of the hinge-line, 

 ■which is crenulated, equalling or exceeding the greatest width of the 

 shell below. Dorsal valve concave, deflected around the front and sides. 

 Surface marked by fine closely arranged radiating striae, which are 

 crossed by obscure concentric lines of growth. Interior surface granu- 

 lose, and more or less striate. 



