TRANSACTIONS OP THE SECTIONS. 91 



same character. The surface of fracture was partiallj^ covered with a 

 number of small and exceedingly thin scales, almost perfectly transpa- 

 rent. They adhered to the brown matter with such tenacity that it was 

 difficult to detach them for the purpose of examination by the micro- 

 scope. Within the fluted base of one of the teeth, the white and brown 

 substances are united together very irregularly, and in some places are 

 combined with a third substance of a coaly nature, which burns without 

 flame or smell, upon a heated iron. The enamel is in many places 

 finely preserved. It has a yellowish transparency, and exhibits a sort 

 of ramified structure both by reflected and transmitted light, the re- 

 flected tints having in some places a sort of nacreous lustre. 



During the examination of the brown substance by which the cavity 

 of the tooth is fllled, the author noticed something like a veined struc- 

 ture ; and upon a narrower inspection succeeded in tracing a regular 

 structure in every part of it, exactly similar to that of a nodule of 

 agate. The brown substance, which consists of bituminous and calca- 

 reous matter, seems to have been deposited and indurated in successive 

 layers concentric with one mould of enamel, by which they were in- 

 closed. The annexed sketch, on a magnified scale, will convey some 

 idea of this structure, which Sir D. Brewster found more or less di- 

 stinctly developed in every tooth. Upon subsequently examining the 

 fossil teeth of Burdie-house, deposited by Dr. Hibbert in the Museum 

 of the Royal Society of Edinburgh, the author perceived distinct traces 

 of the same structure in one or two which presented fractures capable 

 of displaying it. 



On the Geology and Thermal Springs of North America. By Dr. 

 Daubeny, Professor of Chemistry and Botany, Oxford. 



In this communication the author gave a rapid sketch of the mineral 

 structure and direction of the mountain chains in North America, with 

 a view of explaining the position which the thermal springs in the 

 same country occupy, with reference to the adjacent rocks. 



He then proceeded to describe the thermal springs themseh'es 

 which he had visited in the course of his visit to the western hemi- 

 sphere. 



1st. In the mountain region of Virginia, west of the Blue Ridge, 



