254 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 11, 



the hard mundicy veinstone was a different and subsequent operation 

 to that of segregating the veinstone itself. 



The Ducktown ores seem, in fact, to be contained in a kind of 

 stock-works produced as gaping fissures in stratified or partially 

 metamorphosed rocks during metamorphism and elevation, and sub- 

 sequently filled up by segregation from the enclosing country or from 

 below during the completion of metamorphic action. These large 

 lodes are connected with numerous smaller fissures filled only with 

 quartz, the metallic sulphurets and oxides appearing to occupy the 

 upper and less compact portions of the larger fissures. That the 

 fissures were filled up by chemical forces and independently of direct 

 aqueous action, is, I think, quite clear, and no modification of the 

 theory of sublimation would account for the phsenomena of the 

 district. 



As, however, some of the quartz-lodes in which there is no surface- 

 gossan have been proved to contain gossan at a moderate depth (a 

 few fathoms from the surface), and as in one case an effort has been 

 made to reach copper-ores of the ordinary kind (yellow sulphurets) 

 by sinking in quartz-lodes within the district, there may be an op- 

 portunity of judging of the nature of these lodes and their contents 

 at greater depth. It seems to me by no means unlikely that large 

 bunches of rich copper-ore may exist either in the gossan-veins 

 beneath the hard floor, or in the quartz-veins where no gossan is 

 presented to view at the surface ; but, until experience has shown 

 some result of importance, it would be unsafe to assume the presence 

 of courses of ore in Ducktown such as are found in other known 

 mining districts. 



Very analogous cases of outcropping gossan of large dimensions 

 have been discovered in Virginia about a hundred miles to the north, 

 and specimens both of the gossan and of the underlying black ore 

 were shown me by persons interested in these mines. I was unable 

 to visit them, and therefore can do no more than direct attention to 

 the fact. 



March 11, 1857. 



Charles Napier, Esq., C.E., and John Brown, Esq., York, were 

 elected Fellows. 



The following communications were read : — 



1 . Description of the Lower Jaw and Teeth of an Anoplothe rigid 

 QUADRUPED (Dichobunc ovina, Ow.) of the size of the Xiphodon 

 gracilis, Cuv., from the Upper Eocene Marl, Isle of "Wight. 

 By Prof. Owen, F.R.S., F.G.S. 



[Plate VIII.] 



The subject of the present description (PI. VIII.) is an almost entire 

 lower jaw with the permanent dental series, wanting only the four 

 middle incisors. The specimen is from the collection of the Mar- 



