NIAGARA FALLS AND VICINITY 163 



cia tubular, radiating on the upper surface from a depressed center; 

 apertures oblique, imbricating, provided with a lunarium ; mesopores 

 short, irregular, decreasing in number from center to margin; large 

 maculae or clusters of mesopores or of zooecia at regular intervals. 



Ceramopora imbricata Hall (Fig. 58) (1852. Pal. N. Y. 2:169, 

 pi. 40E, fig. la-i) 



Distinguishing characters. Depressed hemispheric form, flattened 

 or convex on the lower side; composed of cylindric or subcylindric 

 tubes slightly diverging from the cen- 

 ter, rectangular to plane of upper sur- 

 face; arched or triangular aperture, 

 opening on all sides toward the outer 

 margin, arranged in alternating and 

 imbricating series. 



Fig. 58 Ceramopora imbricata with en- 



Found in the Rochester shale at largement of surface 

 Lockport (Hall) and probably also at Niagara. 



Ceramopora incrustans Flail (Fig. 59) (1852. Pal. N. Y. 2:i6g, 

 pi. 40E, fig. 2a-d) 



Distinguishing characters. Incrusting 

 ,„ ^ habit; cells increasing unequally from a 

 center or point of growth, short, minute, 

 * ' opening obliquely outward and arranged 



Fig. 59 ceramopora incrustans with ^^ quiuCUUX Ordcr. 

 enlargement of surface -r^ i-.i-r>i j 11 iX 1 



h ound m the Rochester shale at Lock- 

 port (Hall); may also occur at Niagara. 



Genus chilotrypa Ulrich 



[Ety. : xe't^o?, lip; rpoTta, perforation] 



(1884. Cin. soc. nat. hist. Jour. 7:49) 



Zoarium small, branching, with a narrow, irregularly contracting 

 and expanding tube; zooecial tubes cylindric or somewhat com- 

 pressed, thin walled, with or without diaphragms; walls minutely 

 porous; apertures elliptic, oblique, the lower margin thickened and 

 elevated ; at irregular intervals maculae or monticules, composed of 

 clusters of vesicles and of zooecia slightly larger than the average 

 occur; interzooecial spaces occupied by vesicular tissue, which is 

 commonly filled by a dense calcareous deposit near the surface. 



