PARSONS : TRIAS OF THE VALE OF YORK. 157 
my opinion that the line of junction must lie somewhere 
between Gfoole and Hook; I am now able to fix it with 
certainty as passing under Gfoole. In a well sunk in 
1878, in Old Groole, the Keuper was reached at a depth of 
46 feet ; it was only pierced to a depth of 8 feet, and the 
Bunter below was not reached. In wells about 200 yards to 
the west, the Bunter is reached without any superjacent 
marl, at a depth of about 60 feet* The boundary line 
between the two formations must therefore lie somewhere 
between these two points. This conclusion is corroborated 
by the fact that if we mark on a map the places where the 
red sandstone and red marl are exposed, or have been struck 
in borings, and draw a line north and south — the direction of 
the strike — through Gfoole, all the places where the Keuper 
occurs will lie to the east of that line, and all the places 
where the Bunter occurs to the west of it, with the solitary 
exception of Reedness, an exception of the kind that proves 
the rule, for here the red sandstone was struck at a depth of 
342 feet, beneath a thickness of 292 feet of red marl. (The 
white gritty sandstone met with at Sandtoft, section 1 in the 
Appendix to my former paper, was, I have now no doubt, 
Bunter and not Keuper.) 
From the above data we are able to calculate approxi- 
mately the dip of the triassic strata, and hence their 
thickness. The dip of the new red sandstone cannot be 
made out in any of the sections in which it is exposed on the 
surface, in consequence of its being always strongly false- 
bedded ; nor by comparison of different well sections, owing 
to the absence of beds marked by characteristic fossils, or 
constant and recognisable lithological characters; but the 
junction of the red sandstone and marl, if no marked uncon- 
formability exists, furnishes us with the required landmark. 
* Section 5, Iog. cit, p. 233. 
