Xxil_ EXPLANATIONS OF THE PLATES. 
ent — alternating beds of sandstone and clay, these last enclosing 
limestone nodules, taking the place of the bituminous schists. 
pecrTrON “It. 
The Old Red System of England and Wales, as given in the general 
Section of Mr. Murchison, with the Silurian Rocks beneath and the 
carboniferous limestone above. 7. The point in the geological scale 
at which vertebrated existences first appear. The three Old Red 
Sandstone formations of this section correspond in their characteristic 
fossils with those of Scotland, but the proportions in which they are 
developed are widely different. The tilestones seem a comparatively 
narrow Stripe in the system in England; the answering formation in 
Scotland, e, f, g, A, is of such enormous thickness, that it has been 
held by very superior geologists to contain three distinct formations 
—e, the New Red Sandstone, f, a representative of the Coal Meas- 
ures, and g, h, the Old Red Sandstone. 
SECTION III. 
Interesting case of extensive denudation from existing causes on 
the northern shore of the Moray Frith. (See pages 198 and 199.) 
The figures and letters which mark the various beds correspond with 
those of fig. 5, and of the following section. The “ fish-bed,” No. 1, 
represents what the reader will find described in pp. 221-225 as the 
* platform of sudden death.” 
SECTION. iF. 
Illustration of a fault in tae Burn of Eathie, Cromartyshire. (See 
pages 204 and 205.) 
