80 MICROSCOPICAL OBJECTS FOUND 



of it being of frequent occurrence. Recent 

 species closely resenabling the above forms, occur 

 in modern beach deposits. 



Fig. 81 is almost the only fragment I have 

 seen in the Charing Chalk really resembling a 

 sponge spiculum, of which it may possibly be a 

 portion. 



Fig. 82 is a calcareous tri-radiate sponge 

 spiculum, from Chalk found, by Dr. Mantell, in 

 the interior of a hollow flint : 



Fig. 83 is a siliceous sponge spiculum, found 

 abundantly along with the last. 



Fig. 84 is a fragment of shell, and figs. 85 

 and 86 are detached calcareous shell prisms, 

 which are very abundant in the Charing Chalk. 

 At first I was led to suppose that these were 

 large calcareous sponge spicula, but, on further 

 examination, I was convinced that they were 

 shell prisms, and that the analogous structures 

 found in flint were of the same nature. I am 

 happy in having had an opportunity of obtain- 

 ing Dr. Carpenter's confirmation of the views 



