240 
woof of synchrony in time. There is nothing to distinguish 
lithologically a grit of the slate rocks from one of the coal senes, 
or even from a tertiary. There is, however, nothing in all this 
to invalidate the conclusions to which, partly from 'J& 
partly from organic contents, and partly from structure a d 
composition, geologists have uniformly arrived, that the g*® a J 
^rk formations ar! wholly different from each o her an^ that 
this difference is not one of recurrence, but that each forms 
^^Vromth^specialities of the Triassic system, the New Red- 
sandstone, I single out one, viz., the prevalence of rock-sal . 
This is a marinf deposit, and occurs sparingly » r° Js ol FaU 
ases hut in excess in these red rocks, whence it if oMainea 
economic use. The saliferous strata are often subjected to the 
action of springs, which dissolve the salt and bn “° U P f “ 
use. The deposits underwent dislocation and denudatio . 
same sea-water, before parting with its salt, had E^many 
sulphate of lime (gypsum), and this action toob P^ ace r i ^ ards \ 
successive quantities of water over the same area , atte 
change of conditions occurred, and the deposit b ? ca .®® ® ov 31 
withday, stored, as it were, for future use A smila r process 
is som- on now in the great salt lake, the Dead bea, ana 
other lakes holding concentrated solutions. ^ be L re ^g n . 
slightly saline waters of rivers, ana the latter become 
06 33 & The* Jurassic system, composed of frequent alternations of 
clay, sandstone, and limestone, may be likened to a port-n onhe 
nresent earth and ocean in the vicinity of the Torres Strait.. i 
similarity is increased by the slight subsidence of some po ation. 
of that coral sea. But here the comparison ends Tte °ohtm 
_ pv : n d was ushered in by the upheaval of the Juia iange, anu 
Ed ^that of the 8 lope y s of the C6te d’Or; in the interval there 
were frequent sudden changes of material, as from the clean san 
luhe coral rag, to the thick and wholly different Oxford clay j 
and entire changes of condition, as from marine beds of the 
lower oolite, to the freshwater and land surfaces above, and then 
a descent again into the sea; and again, an elevation for he 
growth of terrestrial plants, and so cm. An ®* a ®'Ethe 
Yorkshire coast, the observer realizing the fact that al the : sue 
cessive beds were either sea-bottoms or land-surfaces, will ser 
all idea that the pteaeut i. a mete «— * 
The various and dissimilar beds of the oolite, tnoug 
denoting immensely long periods for their fo^aUon point to 
tip evolution of some causation not involved m the visidi 
phenomena, but apart from them. The argumentsof thosewho 
would persist in looking for causation in the rocks, remi 
