British Association for the Advancement of Science. 307 
the bones of the rhinoceros, hyena, &c. are ¢ontained in marl 
beds and stalactite ; and over these the fragments of marine tes- 
tacea, showing the irruption into this cave of a diluvial 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. from his own researches 
during alate visit, and partly through thé kindness of the Messrs. 
Rogers, to whose labors in American geology he paid a just tribute 
of approbation. He then gave’a short sketch of the different 
chains of mountains in the United States. He stated briefty, 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 Seater: 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 Se was vastly 
greater than has hitherto been suppo 
The next paper was on the sruchire of Fossil Teeth, “by Mr. 
Gwen. 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 different 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 bone, as illustrated 
by microscopical examination of the teeth of man, and of various 
existing and extinct animals. 'This paper Soin the results of 
extensive investigations, conducted with Prof. O.’s usual skill and 
thoroughness, on the internal ae of the teeth of various or- 
rs of animals. 
- Dr. Buckland communicated an Account of Footsteps on Sand- 
stone near Liverpool. This interesting discovery was made in a 
quarry on the summit of the peninsula between the Dee and Mer- 
