112 PROCEEDINGS OF THE ACADEMY OF 



FAVOSITES, Lamark. 



Favosites ? mancus ii. sp. Coral a small hemispherical mass, with an ob- 

 tuse apex.; principal cell-mouths very small, sub-circular; those occupying 

 the interstices smaller and angular ; cell-walls strong, prominently raised 

 above the general surface. Cells rapidly enlarging and multiplying by fre 

 quent gemmation. No pores, stria? or diaphragms have been discerned. 



Diameter of polypary, "68 inch; largest cell-mouths, -05 inch in diameter. 



This differs from F. divergent, White and Whitfield the only other species 

 described from rocks of this age in its extremely diminutive proportions, and 

 in the apparent absence of diaphragms. There is perhaps as much reason for 

 referring this species to Conopotcrium as to Favosites. 



Collected by A. Wiuchell, in the Goniatite limestone of Rockford, Indiana. 



Trematopora ? vesiculosa, Win. Specimens undistinguishable from the 

 Iowa species, in their existing state of preservation, have been collected by A. 

 Winchell, at Alan's quarry, in Hillsdale, Michigan. 



Lingula Cuyahoga, Hall. Numerous specimens, not distinguishable from 

 this species, were obtained by the writer from fragments of a hard, calcareous, 

 brecciated rock, quarried from a well on the premises of Judge Alan, at Hills- 

 dale, Michigan. The geological position is apparently in the lower part of the 

 Marshall group. The rock here is the nearest approach in physical charac- 

 ters that has yet been seen to the Goniatite limestone at Rockford, Indiana. 



Occurs also in the "Fine-grained sandstone beneath the coal at Ward's 

 mine, Wethersfield, Trumbull County, Ohio conglomerate wanting." Whit- 

 tlesey's collection. 



DISCINA, Davidson. 



DlSCINA GrALLAHERI, n. Sp. 



Shell of medium size, nearly circular. Ventral valve with the apex sligrTtly 

 excentric ; foramen lanceolate, reaching from near the apex four-fifths the 

 distance to the margin, and acute at both extremities. Surface marked by 

 about fifteen rigid, sharp, sub-equidistant stria 3 , which are somewhat more 

 approximated toward the apex. The striae are less distinct on the shell than 

 upon the cast. 



Dorso-ventral diameter about l'O ; transverse diameter about 1*0 ; distance 

 from apex to dorsal side, *48 ; length of foramen, - 33. 



Found at Hillsdale, Michigan, on the premises of Rev. F. A. Gallaher, in a 

 small loose fragment having the lithological characters of the lower gray 

 portions of the neighboring Marshall sandstone. It occurs also in Col. Whit- 

 tlesey's collection from Girard and Wethersfield, in Trumbull County, Ohio. 



I at first referred the specimens to D. Newb&rryi, Hall, (xvi. Rep. N. Y. 

 Regents, p. 30,) but direct comparison with the types of that species shows 

 that it differs in having more remote, stronger and more regularly equidistant 

 concentric stria?. In its striation it resembles D. grandis, Hall, from the Ham- 

 ilton group, but the form is more circular and the striae are relatively less 

 remote. 



Discina capax, White, (1S64.) Identified in Whittlesey's collection, "from 

 rocks next below the coal canal level, one mile below Girard," and also at 

 " Girard, Trumbull County," Ohio. 



The types of D. Nezvberryi, Hall, (1864,) do not seem to be distinguishable 

 from this species. 



PRODUCTA, Sowerby. 



Producta gracilis, n. sp. Shell small, aperture of the ventral valve form- 

 ing a little more than a semicircle. Ventral valve moderately inflated for a 

 Producta, with flattened, smooth, triangular auriculations ; hinge-line equal 



[July, 



