468 
THE GEOLOGIST. 
near Catrine, and thus reudcring it extremely probalile that such coal- 
measures extend under the valleys of the Eden and the Esk, their southern 
outcrop being ex])osed in the Kaw Eeck, south of Dalston, and their 
northern outcrop at Canobie. Tliese Carboniferous strata may not be rich 
in coal, but they contain the limestone of Ardwick, Leebotwood, and Bal- 
lochmoyle Braes (formerly termed a freshwater one), and show a great 
development of coal-measures, which are useful to be known if it be only 
to show the depth that has to be sunk through before the middle and pro- 
fitable coal-fields of Whitehaven and Canobie can be reached. This por- 
tion of the coal-measures, both in Scotland and the north-west of England, 
has generally been termed Permian, and summarily dismissed as unprofit- 
able " red measures." In the author's paper on the Ballochmoyle lime- 
stone,* it was shown that a great thickness of unprofitable coal-measures 
had to be traversed before the profitable coal-field at Common could be 
reached, in that district some 550 yards. 
The Canobie section exposes far more coal-measures above the limestone 
than the one at Ballochmoyle, at least 200 yards, and it shows a passage 
of Carboniferous into Permian beds, so far as the eye can detect, better 
than any that has hitherto com.e under his observation. The strata of 
these two formations in the bank of the river above the bridge at Canobie 
from the fine breccia into the underlying clays and shales are most difiicult, 
if not impossible, to separate from the red shales and sandstones seen be- 
tween that point and the bridge there. 
The district about Canobie, Penton, and Longtown, has been described 
at length by Mr. Edmund Gibsone, in an elaborate and well-illustrated 
memoir printed in the Transactions of the North of England Institute of 
Mining Engineers. f In the Penton Linns' section that author describes 
the mountain-limestone seams of coal, in the Penton railway section the 
millstone grit series, and in the Canobie coal-field the middle series ; and 
he shows a fault on the south of the latter coal-field which throws the coal- 
measures down and brings in the Permian strata. All the red measures 
south of this fault Mr. Gibsone appears to consider Permian, and the fault 
which brings them in he calls the Great Permian Fault. After examining 
these red measures, the author said he had come to the conclusion that 
although a portion of them are Permian strata, as Mr. Gibsone describes 
them to be, a great part of them are unquestionably upper coal-measures. 
The profitable Canobie coal-field, like that at Common in Ayrshire, belongs 
to the middle or valuable coal-field ; but there is also at Canobie a great 
thickness of upper coal-measures containing a seam of limestone, in all re- 
spects like the Ballochmoyle Braes, near Catrine, the Ardwick and Lee- 
botwood limestones. Consequently, the Permian fault should be called by 
some other name, say the Great South Fault. 
Practical mining engineers have frequently classed aU the red and varie- 
gated beds which they find in the upper part of the coal-measures as " red 
measures " or Permian strata. iSTow, there is no doubt often great difficulty 
in drawing the line of demarcation between the upper coal-measures and 
the Permian strata, and it is possible that, in some sections, one may pass 
into the other, as appears to be the case in the river-section above the 
bridge at Canobie, previously alluded to, but in the north-west of England 
this transition is not generally to be seen, The further we investigate the 
* On some Upper Coal-^feasures containing a Bed of Limestone, at Catrine in Ayr- 
shire. (' Quarterly Journal of the Geological Society for August, 1802,' p. 437.) 
t A geological paper on the Border Districts of Dumfriesshire, Cumberland, and part 
of Koxburghshire, includius; the coal formation of Canobie, etc., by Edmund Gibsone. 
(Vol. xi. p. 65.) 
