TRENTON LIMESTONE. 69 



lamellae or diaphragms, but are constricted near the upper surface of the specimen, and 

 again at a point some distance below. 



Fig. 3 a. The upper surface of the specimen, showing the quadrangular or rhomboidal openings upon 



the outside. 

 Fig. 3 i. A portion of the same enlarged, with a few of the openings, showing the aperture of the 



cylindrical tube within. The opening above is not entirely circular. 

 Fig. 3 e. Vertical section of the cylindrical tubes through the centre of the mass, as they appear on a 



weathered surface. As these converge towards the base, the ends only are seen, as shown in 



the figure. 

 Fig. 3 d. Three of these tubes enlarged, showing a contraction or stricture near their upper termination, 



and the same below. 



Position and locality. In the Trenton limestone, Carlisle, Pennsylvania.* 



105. 3. STREPTOPLASMA CORNICULUM ( n. sp.) . 

 Pl, XXV. Figs. 1 a, b, e, d, e. 



Turbinate, curved near the base, which terminates in an acute point, somewhat rapidly 

 expanding above ; cup profound ; lamellae about sixty ; surface marked by strong lon- 

 gitudinal lines indicating the lamellae, which are crossed by fine concentric wrinkled lines. 



Length varying from three-fourths to one and a half inches. 



This species has usually been referred to Cyathophyllum ceratites of Goldfuss ; but an 

 examination of its structure proves that it does not belong to the Genus Cyathophyllum. 



Fig. 1 a. A small nearly perfect individual. 



Fig. 1 ft. A larger specimen. 



Fig. 1 «. A short and less curved specimen, with the surface distinctly marked. 



Fig. 1 d. A portion of the surface of the last enlarged. 



Fig. 1 «. Vertical section on one side of the centre. 



Position and locality. This species occurs principally in the thin shaly layers intervening 

 between the calcareous beds in the lower part of the rock. It is found at Trenton Falls, 

 Middleville, Turin, Watertown, and at numerous other localities. {State Collection.) 



' The species described by Defrance is from a very ancient rock, according to the remarks of De Blainvilu, 

 and, we may presume, from the same formation as our own, rendering it the more probable that the two are identical 

 species. The only observed difference between the two is in the apertures of the tubes, which, in our species, are not 

 circular as represented in the figure of De Blainvh-le. The figure of Coscinopora sulcata ( Goldfuss, Plate ix. 

 fig. 19 6) resembles very closely the upper or inner surface of our coral ; but the species from the lead-bearing lime- 

 stone of the West, usually referred to Coscinopora sulcata, is totally different from our species, and probably distinct 

 from that of Gouittm, since that species is referred by him to the Jura limestone. 



