61 



Sir THOMAS BRISBANE in the Chair. 



The following Communications were read : — 



1. Summary of the Discoveries liitherto made in the Ossife- 

 rous Beds of the Basins of the Forth and Clyde. By Dr 

 Hibbert. 



Thk autlior gave a summary of the discoveries which had taken 

 place during the course of the session relative to the ossiferous beds 

 of the basins of the Forth and Clyde. The additional information 

 contained in his paper comprised, in the first place, an account of the 

 older class of strata upon which the carboniferous group of rocks (in 

 which saurian remains had been found) were supposed, in an uncon- 

 formable position, to rest. Some of tliese were referred to a system 

 of beds, which geologists consider as of a newer transition class, in- 

 termediate to grauwacke schist and coal strata. Thus, it was found 

 that a peculiar liard and gray sandstone, containing mica, and occasion- 

 ally alternated with siliceous schist, — which in Shetland succeeds to 

 clay-slate ; which, near Loch Ness, succeeds to a transition granite ; 

 and, on the north of the Tay, to grauwacke schist, — was thrown up on 

 the south of the Forth, near North Berwick, in the form of immense 

 severed beds or fragments, shewing that this transition-rock (an im- 

 portant one in the series of Scottish strata) is to be regarded as in 

 some places fundamental to the coal measures of the district. This 

 older grey sandstone is also alternated, either with aluminous strata 

 of the same general character, or with a hard sandstone of a reddish 

 colour. 



The carboniferous deposits inclosing saurian and other remains 

 which rest in an unconformable position upon these strata, were for- 

 merly shewn to contain inferior beds of sandstone, shale, and fresh- 

 water liuiestone, together with very thin seams of coal and ironstone; 

 and to be succeeded, first, by a limestone containing marine shells, 

 encrinites, corallines, &c., and afterwards by extensive coal measures 

 which formed the upper beds of the series. This is shewn in the fol- 

 lowing general section of the strata connected with the limestone of 

 Burdiehouse. 



