150 



PALJEONTOLOGY OF NEW-YORK. 



and tlic apertures in some specimens are nearly circular. Where well preserved, the caliclc or 

 margin of the aperture bears three, four or live minute spinules which under the magnifier ap- 

 pear like dark points. In the greater proportion of specimens, however, these spinules are worn 

 off without changing the form or appearance of the aperture. 



Fig. 1 a. A fragment with parts of several branches, showing the tuberculous character very 



distinctly. 

 Fig. 1 i. A smaller bifurcating branch of the same species. 

 Fig. 1 c. A small branch scarcely showing the tuberculous character. 

 Fig. 1 d. The surface magnified, where the apertures are close together, and irregular in their 



arrangement. 

 Fig. 1 e. A surface somewhat worn, where the openings are less closely arranged. 

 Fig. 1 /. The apertures of several cells, showing minute points or spinules around the aperture. 

 Fig. I g. A transverse section of a stem enlarged, showing the internal structure. 



Position and locality. In the shale at Lockport, particularly in the thin calcareous layers, 

 and occurring where the softer portions have been decomposed and carried away by rains. 



(Stale Collection.) 



540. 2. TREMATOPORA COALESCENS (n. ;?j9.). 



PL. XL A. Fig. 2 a, 6. 



Corallum consisting of coalescing branches, somewhat flattened ; surface smooth ; apertures 

 of cells round-oval, not contiguous ; intercellular spaces solid ; transverse section indistinctly 

 fibrous. 



This species can be distinguished by its peculiar mode of growth, in specimens where this 

 character is preserved ; and in fragments of branches, the more nearly circular form and \vider 

 separation of the apertures are sufficient to distinguish it. The wider interspaces between cells 

 probably gives a more solid structure and appearance to the ends of the stems. In some 

 examples, this species appears to increase by successive laminffi overspreading portions which 

 have ceased to increase by extension of the cells. The calicle is thin and fragile, being often 

 worn away entirely, leaving a perforated surface. 



Fig. 2 a. A fragment showing several branches coalescing. 



Fig. 2 b. A portion of the surface enlarged, showing the apertures where worn and unworn. The 

 cells are to some extent unequally distributed over a part of the coral. 



Position and locality. In the soft calcareous shale of the group at Lockport. 



