( 56 ) 



EEA OF THE OLD EED SANDSTONE. 

 FISHES ABUNDANT. 



We advance to a new chapter in this ma,rvellons history 

 — the era of the Old Red Sandstone System. This term 

 has been recently appHed to a series of strata, of enor- 

 mous thickness in the whole mass, largely developed in 

 Herefordshire, Shropshire, Worcestershire, and South 

 Wales ; also in the counties of Fife, Forfar, Moray, 

 Cromarty, and Caithness ; and in Hussia and North' 

 America, if not in many other parts of the world. The 

 particular strata forming the system are somewhat difter- 

 ent in different countries ; but there is a general cha- 

 racter to the extent of these being a mixture of flag- 

 stones, marly rocks, and sandstones, usually of a laminous 

 structure, with conglomerates. There is also a schist 

 showing the presence of bitumen ; a remarkable new 

 ingredient, since it is a vegetable production. In the 

 conglomerates, of great extent and thickness, which form, 

 in at least one district, the basis or leading feature of the 

 system, inclosing water-worn fragments of quartz and 

 other rocks, we have evidence of the seas of that period 

 having been subjected to a violent and long-continued 

 agitation, probably from volcanic causes. The upper 

 members of the series bear the appearance of having been 

 deposited in comparatively tranquil seas. The English 



