NIAGARA GKOUP. 



117 



departures from these characters, clue perhaps to accidental causes, which present almost specific 

 differences. 



Fig. 1 a. A single cell with a lateral bud on one side. The weathered portion near the top of 

 the specimen shows very distinctly the transverse dissepiments. 



Fig. I h. A specimen cut obliquely, showing the transverse dissepiments in the inner circle of 

 the cell. 



Fig. 1 c. A group formed by budding from a single stock below. One of the buds is broken off 

 near the base. The exterior surface is well preserved in this specimen, showing the 

 fine transverse stria. The outer circle is distinctly cellular from above, while the 

 centre is solid. The base of this specimen is covered by an incrusting coral. 



Fig. 1 d. A small group, showing one mode of budding. The continuation of the righthand 

 portion of the figure has been broken off. 



Fig. 1 e. A cylindrical specimen, contracted at intervals from intermitted growth, and showing 

 a tendency to budding at these points. On the lefthand side, at a, a, are two buds 

 broken off; and on the righthand side, at b, b, b, are the germs of three other buds 

 which have not expanded. 



Fig. 1 /. A portion of fig. 1 a enlarged, showing the transverse dissepiments uniting the lamellae. 



Fig. 1 g, h. The cell natural size and enlarged, showing the denticulated appearance of the la- 

 mellae, arising from the dissepiments being partially preserved at the junction with 

 the laniellce. The inner and outer portions of the cell are distinctly shown. 



Fig. 1 i. A vertical section of the cell. 



Fig. 1 k. A fragment showing the ends of several stems standing out above the weathered surface, 

 having the exterior portion still cellular, while in many of them the centre is solid. 



Fig. 1 ?. A polished section of a less crystalline specimen, showing the ends of several stems. 



Fig. 1 in. A part of a larger group, showing the manner of budding and increase. 



Fig. 1 w. A single stem with two buds in the lower part, which are broken off near the stock; 

 while near the upper part the buds are numerous, and thrown out on all sides. The 

 surface of the specimen is somewhat worn, showing the lamellar structure of the 

 outer circle, while the transverse septa are obliterated. 



Fig. 1 o. A longitudinal section of several stems, showing the transverse dissepiments, which, 

 near the base of one stem are bent downwards in the middle, and are otherwise 

 irregular in other parts of the stem. 



Fig. 1 p, r. Longitudinal sections from two different groups, showing irregularity in the trans- 

 verse septa of the centre of the cell. 



Position and locality. This coral is quite abundant in weathered specimens of the lower 

 part of the limestone of the Niagara group at Lockport, but is rare in other places in New- 

 York. (State Collection.) 



