132 THE OLD BED SANDSTONE. 



the Lower Old Bed," the " Middle Old Bed," and th< 

 " Upper Old Bed," each series differing not only in thi 

 composition of its strata, but in the character of its fossi 

 contents. But whatever its variations, there is, throughou 

 Europe at least, a marked prevalence of reddish-colourei 

 sandstones and slaty shales; hence the name "Bed" ii 

 allusion to this colour, and the term "Old" because i 

 lies beneath the coal-measures, and in contradistinction t 

 another series of red sandstones (the New Bed) that lie 

 above them. The system is also frequently termed th 

 "Devonian," because a portion of it is well developed i 

 Devonshire a term chiefly introduced by Sir Boderic 

 Murchison, to harmonise with his geographical nomencL 

 ture of Silurian and Permian. So much for name an 

 mineral composition ; let us now try to catch a glimpse < 

 the physical conditions under which it was deposited, an 

 the kind of life that peopled the land and waters. 



Beyond a few scattered indications of the ancient disti 

 butions of sea and land, geology can obtain no more. Or 

 formation is so frequently overlaid by portions of later fo 

 mations ; so many portions have also been removed I 

 waste and denudation ; and perhaps still greater expansi 

 are hidden by the ocean, which covers nearly three-fourtl 

 of the earth's known surface, that we can merely indica 

 by disconnected patches the seas in which they were d 

 posited. In the case of the Old Bed Sandstone, whi< 

 occupies considerable areas both in the Old and New World 

 we cannot trace either the extent or configuration of i 

 seas, but we catch occasional glimpses of their shores in t] 

 conglomerates which must have formed their pebbly beach( 

 and in the worm-trails and burrows, the crustacean trad 

 the rain-prints, and sun-cracks on the surface of the san 

 stones which must have then spread out as shallow ai 

 alternately exposed sands. Strange revelations these of t' 



