2*48 Mr. J. Lycett on the Fossil Conchology of the 



how a narrow strap-formed apparatus is to work out a circular 

 hole. But having this powerful siliceous organ at hand, cer- 

 tainly capable of penetrating calcareous substances, it would be 

 unlike the direct and simple operations of nature were another 

 one provided. It is more likely that some mode of application 

 is effected by which the ordinary prehensile tongue of the Gaste- 

 ropod is turned into a rasping or drilling instrument. The 

 wearing down of the anterior spines appears favourable to this 

 opinion. 



EXPLANATION OF PLATE VIII. 



Fig. 1. A portion of the epidermis from the anterior cushion-like swelling of 

 the mantle of Saxicava rugosa, seen in the compressor, exhibiting 

 large crystalline bodies. 



— 2. Some of the crystalline bodies from the same after having been six 



hours in nitric acid. 



— 3. The foot and mantle of a small foreign Patella found dried up in an 



excavation, showing the arrangement of the crystalline bodies. 



— 4. A group of the same crystalline bodies more highly magnified. 



— 5. Four of the same bodies exhibiting radiating fractures caused by the 



action of the compressor. 



— 6. A portion of the convex surface of the foot of Teredo norvegka, 



as seen in the compressor, exhibiting crystalline bodies. 



— 7. A group of the same bodies more highly magnified. 



XXVI. — Notes on the distribution of the Fossil Conchology of the 

 Oolitic Formations in the vicinity of Minchinhampton, Glouces- 

 tershire. By John Lycett, Esq.* 



The following remarks have been written chiefly with a view to 

 illustrate the contents of the author's cabinet, premising that the 

 objects in question constitute materials fitted rather for private 

 study than for public demonstration. The bones of gigantic 

 Saurian reptiles, of fishes, the shells of great Cephalopods, are 

 appreciated even by the uninstructed spectator. They speak to 

 his senses of a creation distinct from that which he sees around 

 him, and he is prepared to hear of further wonders when the 

 voice of comparative anatomy tells him of their organization and 

 consequent habits. None of these fall within the scope of my 

 remarks ; they are absent : we know that they existed contempo- 

 raneously with the deposition of these rocks and their included 

 fossils : Stonesfield in this country, Pappenheim and Solenhofen 

 in Germany assure us of this. Speaking with the caution which 

 the subject demands, it may be asserted that the conditions of 

 sea-bottom in our neighbourhood, though varying considerably 

 during the time which was required for an accumulation of 400 

 feet in vertical thickness of solid rock, and the creation and ex- 



* Read before the Cotteswold Naturalists' Club, August 8, 1848. 



