FROM THE YORKSHIRE CHALK. 



13 



Fig. 5. which is reduced from a specimen thir- 

 teen inches in length, will shew the general form 

 of this species : the bottom is pierced by a single 

 canal, which about an inch and a half higher, ap- 

 pears divided into eight or ten : this number is 

 not materially encreased at the top, where the 

 canals are scattered over the surface, and not 

 crowded together as in the last species 

 nexed figure, {Jiff. 6.) 

 which is of the natural 

 size, shows the appear- 

 ance of the summit : it 

 will be seen, that the 

 highesfpart is'of a lessf 

 size than the rest of the 



fossil, and forms assort of crown. The specimen 

 figured is considerably compressed, so that in the 

 sketch it appears broader in proportion to its length 

 than it would haveMone had it been of its natural 

 form. 



I This species is rare : besides the specimen from 

 which the above description was taken, I have 

 only met with two or three fragments. 



Spongia. 



1. Sp. catablastes. — Inversely conical, with a considerable depression at 

 the crown : from ten to fifteen arms projecting downwards from the 

 lower part of the body. Fig. 7. 



Of this beautiful fossil, 

 (fig. 7.), only one specimen 

 has hitherto been discover- 

 ed: but as the characters 

 are very well marked, it will 

 not, I hope, be thought pre- 

 mature, to consider it a new 

 species. Nothing can be 

 said respecting the length 

 of the stem, as it had unfor- 

 tunately been lost when the 

 specimen was taken from 

 the face of the cliff: the 

 whole body is covered with 

 irregular depressions, which 

 on the superior surface, and 

 in the neighburhood of the 

 side arms, take a flexuous 



