340 



THE GEOLOaiST. 



kind." The remark last quoted bears directly on the point noticed 

 in the ragstone hassock in my quarry. 



In the grey Shanklin sand these nodules abound in some localities. 

 I have observed them in Sussex, in Surrey, in the Isle of Wight, 

 near Yentnor, and in many parts of Kent. In vol. iv. (p. 35) of the 

 Geological Society's Proceedings, Dr. Mantell writes, " Mr. Bensted 

 having long paid attention to this subject, submitted to my inspec- 

 tion several specimens of Rostellaria, Trigonia, and other shells, the 

 cavities of Vv'hich were filled with a dark-brown substance, in many 

 respects identical with the nodular and irregular concretions of 

 coprolitic matter which abound in the surrounding sandstone. At 

 the same time, Mr. Bensted expressed his conviction that the car- 

 bonaceous substance was derived from the soft bodies of the mollusca, 

 and that the concretionary and amorphous portions of the same 

 matter dispersed throughout the sandstone of the bed were fossilized 

 masses of the soft bodies of the animals disengaged from their shells, 

 and which had floated in the sea until enveloped in the sand and 

 mud which is now converted into the sandstone called the Kentish 

 Kag. The evidence collected by Mr. Bensted appears to me so con- 

 clusive and so confirmatory of the opinions previously stated, that 

 I beg to place before the Society the following abstract of his corre- 

 spondence with me upon the subject ; — ' The bed of Kentish Eag in 

 my quarry, which lies immediately beneath the stratum that contained 

 the remains of the Iguanodon, abounds in the usual shells of the 

 Lower Greensand, but mose particularly in Trigoniae (generally T. 

 alaformis), and there is an abundance of a dark-brown coprolitic- 

 looking substance, of which I send specimens. 



" ' In some instances this material actually forms the entire casts of 

 the univalves and bivalves, and I think there can be no doubt that it 

 is derived from the soft bodies of the animals which inhabited the 

 shells found in connection with it fossilized in this peculiar manner. 

 There are many examples which look more like true coprolites of 

 fishes, and some of them contain shells partly crushed, as if they had 

 been the undigested contents of the intestinal canal. I am therefore 

 inclined to think that the dark material which now occupies the 

 shells was the soft body of the mollusk ; that those masses of a con- 

 cretionary form which are embedded in the stone are coprolites ; and 

 that the shapeless portions of this substance distributed in the rock 

 have originated from floating masses of the bodies of the dead shell- 

 fish. In illustration of the manner in which such an accumulation 

 of materials as I find in my quarry may have been formed, I beg to 

 call your attention to the following extract from the American Jour- 

 nal of Science : — " One of the most curious phenomena of the year 

 1S3G has been the fatal eflect of an epidemic disease among the mol- 

 luscous animals or sliell-fish of the Muskingum Eiver, Ohio. It com- 

 menced in April and continued until June, destroying millions of 

 tliat quiet retiring race which peoples the bed of streams. As the 

 animal died the valves of the shell opened, and decomposition com- 

 mencing, the muscular adliesions gave way, and the fleshy portion 



