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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Feb. 5, 



inspect the contortions in this Frenchland Burn and not be led to 

 believe that at the period when this region underwent violent commo- 

 tions, the curvatures and fractures most easily and naturally occurred 

 in the graptolitic schists, which are much the softest in the series of 

 these intractable and hard rocks. From their same soft quality, these 

 schists have also been the more easily denuded, and hence, where no 

 great and decided transverse rents afford the streams a course across 

 the strata, their feeders or rivulets have frequently found their way 

 along longitudinal depressions of schist, parallel to the strike of the 

 strata. 



The little which fell under my own observation to the south of 

 Moffat is scarcely worthy of notice, now that the details worked out 

 by Mr. Harkness are known ; but I may note that, even in travelling 

 from Beattock to Lockerby, it struck me that the chief axis of that 

 tract, so much covered with drift and only exposing imperfect sec- 

 tions here and there, would be found to pass by a spot near Nether- 

 cleugh into the chain on the E.N.E., and to range by Dumfries on the 

 W.S.W. Unquestionably the strata at Lockerby dip to the S.S.E., 

 and as all the rocks near Torthorwald, together with those of the 

 country south of that line, have the same inclination as laid down 

 upon a map sent to the Geological Society by Mr. Harkness, it is 

 natural to infer, that a powerful anticlinal passes somewhere near 

 Dumfries. I suggested, indeed, to Mr. Harkness that such would 

 prove to be the case, and his researches confirmed my anticipation, 

 and led him to mark what may be called the anticlinal of Dryfe 

 Water, the lower part of which river, before it empties itself into the 

 Annan near Torwood, flows in accordance with the strike of the 

 ancient rocks. I apprehend that there are many more such anti- 

 clinals in Dumfriesshire, if we could detect them. Whether the 

 Criffel granite be, as Mr. Harkness suggests, the cause of this flexure,. 

 I have not satisfied myself ; but, if so, it does not throw up any strata 

 in which Silurian fossils occur. It must indeed be admitted that the 

 purple and reddish hard greywacke of the tract near Dumfries has as 

 antique an appearance as any of the rocks of this region. It more 

 resembles the unfossiliferous rocks of St. David's and other places in 

 Wales to which the Government surveyors have restricted the term 

 " Cambrian," than any rocks I saw in this region of Scotland. 



On the whole, there being scarcely any other fossils than Grap- 

 tolites and certain obscure Orthoceratites with Annelida in the 

 schists of Dumfriesshire, it is difficult to infer from such organic re- 

 mains alone what is the age of the chief masses of strata in which 

 such forms only are repeated. Judging by analogy, and referring to 

 the portion of the Silurian rocks which in other regions has been 

 found to contain the greatest number of Graptolites, Mr. Harkness 

 has arrived at the conclusion that much of this region — under a very 

 different type — may represent an upper portion of the Lower Silurian 

 rocks. In my opinion he places these strata too high in the series ; 

 and the inference from all that we now know is, that they probably re- 

 present that great mass of Welsh schist which underlies the Llandeilo 

 or Bala limestone, but is still superior to the lowest zone of Silurian life. 



