103 



presents a vertical change of level of about 200 feet; but it is not, 

 like the faults before alluded to, rounded off, and therefore the 

 author infers that it is of more recent orijrin. 



Some observations are then offered on the position of the trap in 

 the neighbourhood of Babbacombe ; and it is shown, that in the hill 

 to the east of the town it rests on shale, and is overlaid by beds of 

 shale and limestone, the trap dipping to the south-west conformably 

 ■with the stratified deposits. At its lower surface it adheres firmly 

 to the shale ; but at its upper no such adhesion occurs, though the 

 bed which rests upon the trap is moulded into its outline. From 

 this phgenomenon, and the absence of all marks of disturbance, the 

 author infers, that the trap was a submarine lava current, on which the 

 superincumbent limestone and shale were subsequently deposited. 

 In other instances, however, as in the hill between Torquay and 

 Tor Abbey, the limestone appears to have been violently disturbed, 

 the beds of new red sandstone on the flanks of the hill being in a 

 vertical position. 



In conclusion the author offers some remarks on the drainage and 

 destruction of the lake which he supposes to have occupied the site 

 of the Ballemarsh and Bovey Heathfield. 



A paper, entitled, " Some Facts in the Geology of the Central and 

 Western Portions of North America, collected principally from the 

 statements and unpublished notices of recent travellers," by Henry 

 Darwin Rogers, Esq., F.G.S , was then begun. 



December 3. — Major-General Lord Greenock, F.R.S. Ed., of 

 Carlton Place, Edinburgh ; David Milne, Esq., F.R.S. Ed., Advo- 

 cate, of York Place, Edinburgh; Coulthurd, Esq., Captain in 



the Bengal Artillery; John Rofe, jun., Esq., of Bernard Street; 

 Rev. James Bowstead, Fellow and Tutor of Corpus Christi College, 

 Cambridge; Charles Hastings, M.D., President of the Literary and 

 Philosophical Society of Worcestershire, Worcester ; and Rev. 

 Josiah Bull, M.A., of Newport Pagnel, Buckinghamshire, were 

 elected Fellows of this Society. 



The reading of Mr. Rogers's paper was resumed and concluded. 



Mr. Rogers states that he is indebted for the greater part of the 

 facts contained in his communication to Mr. Sublette, a gentleman 

 engaged for eleven years in the fur trade; but that he has also ex- 

 tracted from the journals of Long and Lewis, and Clerke and Nutt- 

 hall, such observations as bear upon the structure of the country. 



The district noticed includes the vast tractextending from the Mis- 

 sissippi to the Pacific, and from the 36th to the 49th degree of North 

 latitude. The principal physical features of the country are the 

 Rocky Mountains ; and the immense plains which extend from the 

 Mississippi to that range, circle round its southern termination, and 

 are prolonged into Mexico, and northward to an unknown distance. 



The Rocky Mountains consist, as far as they have been examined, 

 of primary formations, and their eastern chain, the Black Hills, of 

 gneiss and mica slate, greenstone, amygdaloid, and other igneous 

 rocks. Chains of primary mountains, separated by sandy plains and 

 volcanic tracts, constitute the country between the Rocky Mountains 



