PARSONS : TRIAS OF THE VALE OF YORK. 
155 
seems the more desirable inasmuch as the information yielded 
by well- sections, if not put on record at the time, cannot 
always be obtained afterwards. 
The two members of the Trias — the Keuper, or variegated 
marl, and the Bunter, or new red sandstone — occupy a wide 
low-lying plain, between the hills formed by the outcrops of 
the chalk, oolites, and lias, to the east, and the magnesian 
limestone to the west ; the soft and easily-weathered nature 
of the triassic marls and sandstones having caused it to 
undergo a greater amount of disintegration than the harder 
limestones. Over this area the trias is, for the most part, 
covered up with the gravels, sands, clays, &c, mentioned in 
my former paper, only isolated patches rising to the surface. 
These patches are the summits of mounds of trias left by 
erosion, while the intermediate hollows have been filled up 
and levelled over with the recent deposits. Similar mounds, 
not reaching the surface, may be traced in places under the 
alluvial deposits by means of well-sinkings. The junctions 
of the trias with the lias above, and with the magnesian 
limestone below, and also that of the two beds of the trias 
with each other, are concealed by the newer deposits, so that 
it is difficult to make out the relations of the beds to each 
other, and their respective thicknesses. The line of strike of 
the chalk, oolites, lias, and Permian strata, being in south 
Yorkshire and north Lincolnshire, nearly due north and 
south, it may be assumed, without much risk of error, that 
the strike of the intermediate trias is also north and south, 
and the dip therefore to the east. 
The Keuper, where met with, presents its usual characters 
as a red and green marl, with indurated shaly bands, and 
layers of gypsum. It rises to the surface in the Isle of 
Axholme, forming a low hill, extending from Haxey, by 
Epworth, to Belton ; and another at Crowle, in Lincoln- 
shire; and it is reached, by borings, at Reedness, Gfoole, 
II 
