266 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 19, 



tion. At what period this denudation took place we have no means 

 of determining ; but a considerable amount of destruction must have 

 occurred during the pleistocene period ; for the beds which represent 

 this formation in some portions of the South of Scotland consist 

 almost exclusively of sand and gravel, the former of which has been 

 derived from the abraded sandstone, whilst in the latter we have 

 sometimes fragments of the higher breccia. It is, however, on the 

 whole probable that the sandstones and their accompanying strata 

 had suffered a great amount of denudation at a period antecedent to 

 the glacial epoch. 



Previously to this denudation, it would appear that there existed 

 over an area which is now exclusively occupied by Silurians and Car- 

 boniferous rocks, thick deposits of a newer age, having their lower 

 beds composed of breccias and intercalated sandstones ; above which 

 were red sandstones greatly false-bedded ; succeeded by hard breccias ; 

 the only remains of which in Scotland are to be found in the neigh- 

 bourhood of Dumfries, and thin-bedded sandstones, of which only 

 slight traces now remain. The preservation of the isolated patches 

 seems to have resulted from subsidences which have dragged down 

 into hollows these newer strata, the harder Silurians on their margins 

 protecting them from total destruction. 



Age of the Sandstones and Breccias. — With respect to the age of 

 the sandstones and breccias of the South of Scotland newer than the 

 Carboniferous formation, — we have as yet obtained from them no fossils 

 which will enable us to co-ordinate them with deposits of a like 

 nature elsewhere. Such evidence of the existence of animals as they 

 possess is not capable of affording us much assistance, since the foot- 

 steps obtained from the sandy strata seem to be unique among sedi- 

 mentary deposits ; therefore no definite conclusions can be drawn 

 from them. We are consequently under the necessity of adopting 

 lithological evidence in this matter. Red sandstones similar in all 

 respects to those described are common to many parts of the Trias 

 of England ; but we do not find these red sandstones succeeded by 

 thick beds of breccia, as is the case with those under consideration. 

 Breccias are rare among the Trias, while conglomerates abound in 

 some of the middle and lower beds. We have, however, no conglo- 

 merates in the Scotch red sandstones ; the absence of conglomerates 

 and the presence of breccias show that the lithological characters 

 of the strata will not support the conclusion that these deposits are 

 of the Triassic age. 



We are therefore under the necessity of comparing them with 

 another formation which affords red sandstones. In the Permian 

 series we have sandstones which bear resemblance to those of the 

 South of Scotland. Here likewise we have breccias ; and Mr. Binney 

 has shown * that in the neighbourhood of Brough and Kirkby Stephen, 

 in Westmoreland, the associations and composition of the strata 

 closely resemble those of the deposits in the neighbourhood of 

 Dumfries, so much so, that he concludes the deposits of Westmore- 



* Memoirs of the Literary and Philosophical Society of Manchester, vol. xii. 

 p. 257 & p. 267. 



