1853.] HARKNESS — KIRKCUBBRIGHT SILURIANS. 181 



merely thin outlying portions of those to the westward, lying uncon- 

 formably on the slightly inclined edges of the Silurian rocks, and 

 resembling in position the thin coal-measures found on each side of 

 the Lickey ridge near the Colmers= There are some circumstances 

 in the structure of this portion of the district which would incline us 

 to the belief that the edge of the Silurian and Coal-measure rocks is 

 here rather an old cliif, or other margin of denudation, than a fault. 

 They are, however, explicable also if we suppose the Silurian rocks 

 to have been slightly undulating, and the fault that traversed them 

 likewise wavy, so that in some places it cut through slight elevations 

 of the Caradoc sandstone, and the lower measures (leaving portions 

 of them, now exposed at the surface, on the upcast side), while in 

 other places it cut through higher beds which now abut against the 

 fault, having the top of the Caradoc sandstone a shght distance beneath 

 them. The discovery of Caradoc sandstone in this district beneath 

 the Wenlock shale, in its characteristic and unaltered condition, — 

 that discovery being due to Mr. Sharpe, — is interesting both in 

 itself, and as confirming, were confirmation necessary. Sir R. I, Mur- 

 chison's identification of the quartz-rock of the Lickey Hill, as a 

 metamorphosed Caradoc sandstone. 



\_Note. — The term "Caradoc sandstone" is used here in its old 

 signification, — possibly "Wenlock grits" might be the more appro- 

 priate term for these beds. — J. B. J. July 14, 1853.] 



3. On the Silurian Rocks of Kirkcudbrightshire. By 

 Robert Harkness, Esq., F.G.S., Professor of Geology and 

 Mineralogy, Queen's College, Cork. 



[Abstract.] 



In the Stewartry of Kirkcudbright* the Lower Silurian Rocks, accom- 

 panied by igneous rocks, constitute the great mass of the country. 

 From the intrusion of the syenites and porphyries these lower Silu- 

 rians are much changed both in lithological character and in inclina- 

 tion, being bent into several axial flexures (all apparently intimately 

 connected and possibly contemporaneousf ) by the syenitic eruptions 

 of Criifel, Cairnsmuir, and Loch Doon, and by the porphyry of 

 Tongueland. The silurian deposits are best seen on the coast. Here 

 precipitous headlands form the margin of the Stewartry, and these 

 afford information concerning these strata, which would otherwise 

 be inaccessible ; and here too deposits of a different age are met 

 with. Commencing at the eastern side of the county, we have in 



* In illustration of the observations made in this paper, Mr. Harkness has fur- 

 nished a Map and Section. The former consists of two sheets (Nos. 54 and 55) 

 of the Ordnance Survey Map, of the 6-inch scale, colom-ed geologically, and 

 extends from Barlocco Bay to Borness Point. The latter is a coast-section from 

 Netherlaw Point to Bahnae Head, and thence to Cutters Pool, about two miles up 

 the eastern side of Kirkcudbright Bay. The inclined and vertical beds of the 

 cliffs, with some of the intrusive trap-dikes, are represented in detail, and the 

 Section includes a hypothetical representation of the flexures of the strata, as 

 deduced from the various inclinations which are seen exposed. 



t See also Quart. Journ. Geol. Soc. vol. viii. p. 393. 



