182 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 20, 



the parishes of Irougray, Terregles, and Troqueer, new red sandstone ; 

 l:)eing the western extremity of that which occupies the southern 

 portion of the Vale of the Nith*. At Kirkconnell, the most easterly 

 portion of the syenitic district of Criffel is seen, and this is imme- 

 dately succeeded in the south by silurian strata dipping 25° S.E. 

 At Corbally, in the parish of New Abbey, the representatives of the 

 carboniferous formation make their appearance, and then continue 

 along the coast, round Southerness Point, to near the parish of 

 Colvend, occupying a comparatively low tract of country. Near 

 Southerness the beds consist of limestone which has been wrought ; 

 and they contain the characteristic fossils of the lower portion of 

 the mountain limestone. In this formation, near Arbigland, a small 

 seam of coal occurs, and the strata here have great analogy to those 

 which in Dumfriesshire and Roxbvu-ghshire afford the limestone used 

 for agricultural purposes, and which occupy a position between the 

 coal-field of Cannobie and the silurians which lie northward. In 

 the parish of Colvend the coast consists principally of porphyry and 

 syenite, with altered silurian rock often much contorted. On this 

 coast the representatives of the carboniferous beds are seen between 

 Port Ling and Port a "Warren, and are composed of grits containing 

 fragments of the igneous rocks which occur to the northward. West- 

 ward from Port a Warren, altered silurians and igneous rocks are 

 seen, forming lofty headlands which continue until the representatives 

 of the carboniferous beds again make their appearance a little to the 

 east of Glen Stocken. At the latter locality the igneous rocks and 

 altered silurians are again well-exposed, and east from this spot the 

 grits are wrought for millstones. A small patch of silurians is ex- 

 posed in a small cove at Barcloy, and to the eastward the syenite is 

 found, forming the headlands of Barcloy and Almorness and the 

 shores of the estuary of the River Urr. These extend on the west 

 side to Balcarry Bay, where the silurians again occur, dipping at a 

 high angle southward ; and these strata form the island of Hestan 

 which lies on the south-west side of the Bay of the Urr. The 

 silurians continue along the coast round Balcarry Point, which is a 

 bold headland, and immediately west from this they are succeeded 

 by the grit-beds already mentioned. These continue to form the 

 coast, at Airds, Rascarrel, and Barlocco ; and at Bascarrel search 

 has been made in them for copper. Here they are intersected by a 

 thick vein of pure quartz ; and in some places fissured without con- 

 taining any matter filling up the fissuresf. At Barlocco the grit- 

 beds abound in large angular fragments, which have been derived 

 from the silurian rocks. 



From Barlocco westward the same deposits are seen, varied at 

 Orroland hj beds of limestone, similar in nature and fossil contents 

 to that which occurs at Southerness. These grits continue to Port 



* See Quart. Journ. Geol. Soc. vol. vi. p. 389 et seq. 



t Some of the portions of rocks fissured present a very singular appearance. 

 These, where the strata are horizontal, have their margins surrounded by a raised 

 beading which seems to have resulted from water having penetrated the fissures 

 and fui-nished siliceous matter, which entering into the walls hardened them and 

 rendered them less susceptible of the weathering influence of the sea and atmo- 

 sphere. 



