GENERALISED SUCCESSION OF THE NEW RED SERIES, 
Jurassic Rocks. 
Rheetics. 
New Red. 
Upper Division. 
5. Red marls or shales with some beds of flagstone, more or 
less gypsum and rock salt, and occasional bands of mag- 
nesian limestone. 
4. A thick sandstone series, with a prevalent red tint ; pebbly 
in its middle parts in many localities, and usually more or 
less variegated in colouration nearer its base. Volcanic 
rocks locally occur in the higher parts of this section. 
3. A lower marl or shale group, locally containing some gypsum 
and occasionally also some rock salt. 
Lower Division. 
2. A magnesian limestone series, largely of chemical origin, 
and therefore subject to rapid variations in thickness 
within short distances. It is almost as often absent as 
present. m 
1. An extremely variable group of red sandstones, breccias, and 
conglomerates, generally most fully developed in the larger 
depressions of the old surface. 
Great unconformity, chronologically equivalent to at least the 
time required for the denudation of 12,000 feet of the older rocks. 
Of the foregoing series the higher members naturally extend 
over the wider area, as the upper beds overlap the lower. ‘This 
happens partly in consequence of the somewhat irregular form of 
the surface upon which these. rocks were deposited ; but, in the 
majority of cases, more in consequence of those irregularities of 
subsidence which appear to have been, everywhere, characteristic 
of the conditions under which all red rocks have been accumulated. 
It should, furthermore, be noted, that whereas the lower group (1) 
of the section, is usually conglomeratic, yet the conditions that 
gave rise to these conglomerates and breccias did not cease with 
the formation of the lowest group, but were continued, wherever 
