Correspondence—Mr. E. Wilson. 95 
East side of England. I need scarcely remind your readers that geolo- 
gists, not omitting the Survey authorities, have long since abandoned the 
belief in the Permian age of Sedgwick and Murchison’s “Lower Red 
Sandstone” of Yorkshire and Durham. “ All along that range” (Not- 
tingham to Tynemouth), says Prof. Ramsay, “the red rocks on which 
the (Magnesian) Limestone rests are now proved to be Carboniferous 
sandstones and shales. . . . . The supposed Rothliegende has 
indeed almost (? altogether) disappeared from the entire area.”! The 
few feet of true dolomitic Magnesian Limestone at Skillaw Clough 
and a few other points in the West of England cannot for one moment 
be compared with the vastly thicker and more extensive deposits of 
Magnesian Limestone on the other side of the Pennine Chain. I 
must also beg to differ from Prof. Hull, when he refers to the Marl 
Slates of the North-east of England as a local and thin formation. 
We find Mar! Slates accompanying the Magnesian Limestone through 
Notts and through Durham. I have lately recognized them in York- 
shire. In Notts they attain in places a thickness of over 100 feet, 
and under Lincolnshire of about 200.2 They maintain throughout 
this wide area a remarkably characteristic facies. Thus Prof. Hull’s 
objections to my argument for the pre-Permian age of the Pennine 
Chain—based on the dissimilarity of the Permian deposits on the two 
sides of that range—are singularly unfortunate. 
This argument is not, however, as Prof. Hull seems to imagine, a 
crucial point in my hypothesis. Even if the Permian deposits of the 
West were closely allied to instead of being so very unlike those on 
the East of the Pennine Chain, this would not demonstrate the post- 
Permian age of that range. Similarity in texture, of fossils, and even 
of “set” or succession, between the rocks of a period in two adjacent 
areas, though no doubt indicating a general similarity in physical 
conditions and in sequence of events, would not suffice to prove 
original continuity of submergence between those areas. (Deposits 
now accumulating on the opposite sides of an island or peninsula or 
in two adjacent lakes may be undistinguishable, and their faunas 
may agree, and yet such areas are either wholly dissevered or only 
connected in a roundabout way.) All idea of direct continuity of 
submergence must even in that case fall to the ground when there is, 
as in the present instance, sufficient independent evidence of the 
existence of an intervening land barrier. HK. WIxson. 
BLOWING WELLS. 
Srr,—A curious phenomenon has recently been brought under my 
notice observable at some of the wells in the uppermost part of the 
Bunter sandstone of this district. These wells “blow” through 
fissures in the sandstone, just above water-level. This is when 
barometric pressure is low, suction setting in as the mercury rises. 
The most remarkable of these wells is one at Solberge near here. 
The blast at this well is conveyed above the ground by means of an 
1 Q.J.G.S. vol. xxvii. p. 245; Guon. Mac. 1872, Vol. IX. p. 339; The York- 
shire Coalfield, p. 482; Gron. Mac. 1866, p. 49; Q.J.G.S. vol. xxv. p. 291. 
2 Q.J.G.S. vol. xxxiy. p. 812. 
