422 



though to a very small extent, in consequence of the complicated 

 dislocations which intei-sect the district. 



Having described, in the above order, the several portions of the 

 great coal-field, and noticed some of its peculiarities of mineral struc- 

 ture, the authors endeavour to ascertain the limits of certain outlying 

 masses of the loxioer red sandstone, of the magnesian conglomerate, and 

 of the neix) red sandstone. From the facts stated, it appears that the 

 coal measures pass, in some instances, in regular ascending order, 

 into the lower red sandstone. In other instances, however, the coal 

 measures appear to have undergone considerable movements of ele- 

 vation before the existence of the lower red sandstone; in as much 

 as the position of the two formations is discordant. Again, though 

 the lower red sandstone forms the natural and immediate basis of 

 the magnesian limestone and conglomerates, yet there are several 

 places, within the south-western limits of the country described, 

 where the conglomerates appear to have been deposited in hollows 

 and inequalities presented by the waterworn beds on which they 

 rest unconformably. From which facts it seems to follow, that the 

 formations described in this paper have undergone, during their de- 

 velopment, two considerable movements, affecting the position of the 

 component strata: 1st, a partial movement of the coal measures, 

 anterior to the deposition of the lower red sandstone ; 2ndly, a par- 

 tial movement, both of the coal measures and the lower red sand- 

 stone, anterior to the formation of the magnesian conglomerates. 



This being the last evening of the Session, the Society adjourned, 

 at its close, to Wednesdav, November the 2nd. . 



