9 
mine," would, if it could be traced the whole distance, 
describe a perfect semicircle. Owing, therefore, to these 
causes, and particularly to the influence of two great conti- 
guous axes upon the strata, it becomes almost impossible 
to follow any single line of section directly across that Coal 
Field. And when Mr. Binney says " that perhaps the best 
plan would be to take a line from the central axis near Sal- 
tersbrooke to Mottram, and then diverge into two lines, so 
as to embrace the whole of the great Lancashire Coal Field, 
and from thence proceed 50 miles," it seems to me impossible 
to accomphsh it. In the first place, the central axis does not 
cross the line of section near Saltersbrooke, but between 
Mottram and Stayley Bridge, and opposite Mottram the line 
of strike is north and south, and the measures dip due west 
at an angle of 45° ; from this point, then, only one correct 
line of section can possibly be taken, and to take any other 
except in this one line must be incorrect. But there is a 
great objection to Mottram as a starting point, and that is, 
that from it the higher strata in the series, as those of Brad- 
ford, cannot be reached at all ; for the levels of the Bradford 
Coal Field are parallel to those of Oldham, and ought to 
be approached by a line of section passing from the Millstone 
grit at Saddleworth through Oldham. In fact, the proposed 
section on the Lancashire side is under similar circumstances 
as if one were contemplated from the Millstone grit at Otley 
by Leeds to Wakefield, i. e. on the line of dip, and thence to 
proceed to Barnsley nearly on the level of the strata.* There 
is also another objection to any society expending much time 
in collecting data with regard to coal strata opposite Mottram, 
because two sections of it are already published. Hall's section 
of the Dukinfield country, which is in every person's hands, is 
very correct, as proved by Mr. Clay's section, which is nearly 
a copy of it ; and moreover, Mr. Hey wood is about to publish 
his section of the same district, in the Literary and Philoso- 
* Barnsley and Wakefield stand upon the same rock. 
