468 



THE GEOLOGIST. 



near Catrine, and thus rendering it extremely probable that such coal- 

 measures extend under the valleys of the Eden and the Est, their southern 

 outcrop being exposed in the Raw Reck, south of Dalston, and their 

 northern outcrop at Canobie. These 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 come 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 diffi cult, 

 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 Is orth 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 all the red and varie- 

 gated beds which they find in the upper part of the coal-measures as " red 

 measures " or Permian strata. Now, 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 ike 

 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-Measures containing a Bed of Limestone, at Catrine in Ayr- 

 shire. (' Quarterly Journal of the Geological Society for August, lbG2.' p. 437.) 



f A geological paper on the Border Districts of Dumfriesshire, Cumberland, and part 

 of Roxburghshire, including the coal formation of Canobie, etc.. bv Edmund Gibsone. 

 (Vol. xi. p. 65.) 



