CLINTOM CEOtTP. 



55 



Position and locality. In the green shales of the group at Sodus, and particularly in the 

 dark greenish shales associated with the iron ore bed at Wolcott. (State Collection.) 



436. 15. LINGULA PEROVATA. 



Pl. XX. Fig. 3 a, b. 



Shell abruptly obovate, as wide as long, the base regularly rounded and the sides much 

 expanded ; beak abruptly acute ; surface marked by fine, rather distant, elevated concentric 

 lines ; intermediate spaces smooth to the naked eye, but exhibiting under the magnifier fine 

 scarcely elevated concentric lines. 



This shell is readily distinguished by its form (being as wide as long), by its distant con- 

 centric strije, and absence of longitudinal striee. 



Fig. 3 a. Specimen natural size. 

 Fig. 3 b. The specimen enlarged. 



Position and locality. In the upper green shale of the group at Rochester. 



437. 16. LINGULA LAIVIELLATA. 



Pl. XX. Fig. 4 a, b, c. 



Shell subelliptical, acute at the beak and broad below ; surface regularly convex, and the 

 sides curving downwards and apparently inwards, surface marked by strong transverse curved 

 and elevated lamellose lines not parallel to the lines of growth ; fine concentric lines of growth 

 visible near the beak on either side ; beak acute, and neatly defined. 



This species is the most remarkable of all the forms of Lingula observed ; the sides below 

 are nearly straight and parallel ; the outline of the upper part and beak is very peculiar. The 

 prominent features, however, are the transverse lamellose lines, which, instead of curving 

 round and tending upwards towards the beak, terminate in the margin, the finer concentric 

 lines of growth being visible only for a little space on each side below the beak. These 

 strong lamellse are equally visible on the inner side of the shell. 



Fig. 4 a. A single valve, preserving the form and character of the shell very perfectly. 



Fig. 4 i. A portion of the surface enlarged. 



Fig. 4 c. The inside of a fragment of the shell of the same species. 



Position and locality. The only perfect specimen of this species which I have seen, is from 

 the late Mr. Vanuxem's cabinet, and was obtained at a quarry near CUnton village, Oneida 

 county. I have obtained fragments of the same species in Ruddock's quarry, east of Clinton 

 village. 



