584 Geological Society, 



A little below the summit, on theS.E, side, rugged, serrated ridges 

 rise through the snow, some of them consisting of a compact tra- 

 chytic rock, with a highly conchoidal fracture, resembling that of 

 hornstone ; but others are composed of poi^ihyritic trachytes of va- 

 rious colours and textures. Near the foot of the great cone, on the 

 S.E., W., and N. sides, rise numerous smaller ones of pumice and 

 lapilli, from some of which on the N.W. side, streams of basalt or 

 lava may be traced. 



In conclusion, the author expresses his regrets, that the want of 

 organic remains prevents him from determining the comparative an- 

 tiquity of the formations, with respect to those in Europe. In only 

 one instance, the fucoid impressions near Kodj-hissar, did he ob- 

 serve a trace of an organic body in the sandstone ; and the only 

 occurrence of fossils in the limestone series which he noticed, was 

 in the neighbourhood of Sevri-hissar W.S.W. of Angora, where 

 he discovered, in the upper beds of the formation, Limnea and 

 Planorbis. 



March 7. — A notice was first read, on some remarkable dikes of 

 calcareous grit at Ethie, in Ross-shire, by Hugh Edwin Strickland, 

 Esq., F.G.S. 



lliese dikes, which traverse the lias schist, are displayed only 

 at low water. Two of them are parallel to the strata of schist ; but 

 another, which sends off branches in various directions, is in no part 

 of its course parallel to those strata. Their thickness varies from 

 one to three feet ; but that of some of the lateral branches does not 

 exceed three inches. They exhibit no variation in texture or com- 

 position, and show no signs of lamination, but are frequently frac- 

 tured transversely to their direction. The transition from the dike 

 to the lias shale is immediate ; no change being apparent in the lat- 

 ter at the point of junction. The shale, from its greater softness, 

 has been removed between the dikes, leaving them like walls from 

 one to three feet in height. 



These dikes, and similar ones in other places, were noticed by Mr. 

 Murchison, in his examination of the coast of Scotland, in 1826. 



By what means the dikes were produced, the author does not ven- 

 ture to inquire ; his only object being to draw the attention of geo- 

 logists still further to them. 



A paper, on the connexion of certain volcanic phsenomena, and on 

 the formation of mountain- chains and volcanos, as the effects of 

 continental elevations, by Charles Darwin, Esq., Sec. G. S., was 

 then read. 



The author first gave a detailed account of the volcanic phsenomena, 

 which accompanied the earthquake that destroyed Concepcion on the 

 morning of the 20th of February, 1835; and then deduced from 

 volcanic pha^nomena, certain inferences with respect to the formation 

 of mountain-chains, and continental elevations. 



In describing the phaenomcna of the earthquake of 1835, Mr. 

 Darwin quotes the published accounts by Captain Fitzroy* and Mr. 



* Journal of the Royal Geographical Society, vol. vi., p. 319, 1836. 



