British Association for the Advancement of Science. 307 



the bones of the rhinoceros, hyena, &c. are contained in marl 

 beds and stalactite ; and over these the fragments of marine tes- 

 tacea, showing the irruption into this cave of a dihivial current. 



Dr. Daubeny read a paper on the Geology and Thermal Springs 

 of North America. The facts which he was about to detail. Dr. 

 D. said he had become possessed of, partly frorf» his own researches 

 during a late visit, and partly through the kindness of the Messrs. 

 Rogers, to whose labors in American geology hi' fJaid a just tribute 

 of approbation. He then gave a short sketch of the different 

 chains of mountains in the United States. He stated briefly, as 

 the result of his examination of various thermal springs in the 

 U. S., that they gush out in all instances along lines of fracture of 

 the strata, a result similar to that which he had already estab- 

 lished respecting the thermal waters of Europe. Dr. Buckland 

 communicated the contents of a letter from Mr. Lea, stating that 

 the quantity of coal in the valley of the Mississippi was vastly 

 greater than has hitherto been supposed. 



The next paper was on the structure of Fossil Teeth, by Mr. 

 Owen. The internal organization of the teeth in the higher 

 mammalia, as shown by magnified transverse sections, was first 

 described. The curious modifications, which this structure un- 

 dergoes in the Megatherium, the Ichthyosaurus, and fossil fishes, 

 were pointed out in detail, and. illustrated by numerous magnified 

 drawings. It is impossible here to give the details, but the gen- 

 eral result of the investigations is a most important one to geolo- 

 gists, viz. that the difierent genera may be distinguished by the 

 internal structure of their teeth alone ; and therefore, when other 

 characters fail, or a complete tooth is unattainable, generic, nay, 

 perhaps even specific identity, may be established by merely ob- 

 taining a thin slice of one of these fossil teeth. Prof. O. read 

 before the Medical Section, the day previous, a paper on the struc- 

 ture of teeth and the resemblance of ivory to hone, as illustrated 

 by microscopical examination of the teeth of nian, and of various 

 existing ayid extinct animals. This paper contains the results of 

 extensive investigations, conducted with Prof. O.'s usual skill and 

 thoroughness, on the internal structure of the teeth of various or- 

 ders of animals. 



Dr. Buckland communicated an Account of Footsteps on Sand- 

 stotie near Liverpool. This interesting discovery was made in a 

 quarry on the summit of the peninsula between the Dee and Mer- 



