On the Sandstone of India . 
211 
1831 .] 
1, 2, 3 alternating with 4 rare. — Millstone grit, and limestone shale. 
1, 3, and 4 alternating. — Coal formation. 
Now it is obvious, that without No. 2 on the limestone, no division could ever 
have been made between these beds, varying, as they do, inlinitely in thickness, 
in passages into each other, — in alternations with each other, and repetitions. 
But it was found in the Somersetshire coal field, that shafts sunk through the 
horizontal beds of sandstones , came upon the coal strata, inclined at a considerable 
angle, and a section (of the banks of the Avon, I think,) afforded a complete ex- 
planation of the phenomena. The coal strata, mountain lime, and Old Red , were 
highly inclined, as in the section I have drawn above. Upon them rested un- 
conformably” the New Red , the lowest bed of which was a conglomerate, containing 
pebbles of the older rocks, in particular well-marked ones of the mountain lime. 
This unconformable position of the strata has been found to obtain universally 
in England, and, like the horizontal position, is a local phenomenon, with inspect to 
this last circumstance. Of course, if a plain surface is heaved uniformly, it is still 
horizontal ; it is only when one part is more heaved than the rest, that it becomes 
inclined ; I could multiply instances of this in rocks of all ages. 
But to set the question at rest from authority, I will refer to some papers o 
fessor Sedgwick, on the sandstones of Scotland, and the Aew Red of 
northern part of England. — (Geol. Trans, vol. III. part 1.) 
The first of these is a paper on the secondary formations of the island of Aira 
The Professor finds in the cliffs on the coast of Arran, an extensive section o 
the strata exposed to view ; and they are shortly as follows . 
1st. A great thickness of sandstone , with conglomeiate, highly inclined, an 
“ conformable” to the rocks on which it lies. 
These sandstone beds “resemble the harder varieties of the New Red Sandstone of 
England, and exhibit a blotched and variegated character. Below these lie another 
set of beds, the upper portion composed of red and grey variegated blotchy 
marks.” “ Ironstone nodules are interspersed among these beds, some of which 
have that false cleavage so characteristic of portions of the New Red Sandstone .” 
Then come some thin beds of red limestone, containing shells ot the genera Pi > 
duct a and Spirifer , corals and eucrinites. Then come coal beds, with their usual 
vegetable remains. Then a limestone, “ perfectly analogous to the mountain lime, 
w *th producta, orthoceratites, a spiral univalve, encrinites, &c. 
Last of all, in succession, come, “ beds of a highly indurated sandstone of a light 
r ed tinge, alternating with masses of indurated shale of a led , g rey, 7 »' _ 
grey colour ” “ With the above is a calcareous conglomerate, and subordinate to 1 , 
irregular concretions of nearly compact carbonate of lime, not to be distin D uis ic 
from the corn-stone of Herefordshire.” 
These characters, and the absence of vegetable remains, induce him to believe it 
to be the Old Red Sandstone. He sums up his account of it as follows : On a 
great scale it is to be viewed as a red conglomerate, with many subordinate beds o 
sandstone, which cannot, either from the nature of the pebbles, or the cementing pun 
ci ?le, be distijiguished from the newer conglomerate ; neither can the san stone of 
one series be described as differing from that of the other. 
^ he existence, however, in the one deposit of beds of arenaceous granwacke , 
near bottom, and that of the cornstone in the upper part of the formation, 
Wrongly identify it with the Old Red Sandstone. Moreover, independently of any 
Uc h distinctive characters, the intervention of the well-developed groups of the 
Coniferous series, enables us, with certainty , to separate the two gnat deposits of 
Corner ate from each other , and to arrange them with the analogous members 
