230 Reports and Proceedings. 



from nortli to south between the position of this well-marked hori- 

 zon near Keswick and its situation in Borrowdale ; the difference 

 being caused by the above-mentioned fault. The author likewise 

 adduced reasons for the belief that the absence of this fault on the 

 eastern side of the lake was due to the presence of a second fault 

 having a north and south direction, and running along the eastern 

 shore of the lake. As regards the origin of the depression in which 

 Derwentwater is situated, the author held that it is to be ascribed to 

 the ordinary denuding agents, but especially to glacial action. At the 

 same time he could not doubt but that the faults which he had shown 

 to exist had powerfully co-operated in the production of the valley. 

 He did not suppose that faults caused open fissures, which were sub- 

 sequently widened into valleys ; and he was not aware that any one 

 held this view. On the contrary, it was simply held that faults 

 might constitute lines of weakness along which denuding agencies 

 would meet with less resistance than elsewhere ; this being partly 

 due to the inevitable breakage and disturbance of the rocks near the 

 line of fracture, and partly to the fact that rocks of unequal hardness 

 were often opposed to one another for a great distance in consequence 

 of the displacement. This latter cause was specially manifest in the 

 case of Derwentwater — one side of which was composed of the com- 

 paratively yielding Skiddaw Slates, and the other of the igneous 

 series of the Green Slates and Porphyries. And there were unmis- 

 takable proofs that this was due to faulting, and was not caused by 

 the want of conformability, which the author had recently shown to 

 exist between the two formations in question. 



2. " On the Carboniferous Limestone Strata at Southerness, Kirk- 

 cudbrightshire," by William Jolly, H.M., Inspector of Schools. 

 Illustrated by specimens of the fossils there found. 



After referring to the great beauty of the road between Dumfries 

 and Southerness, the author described the Granite, Carboniferous, 

 and Silurian rocks, along the Arbigland shore near that cape. At 

 Southerness occurs an isolated triangular patch of the Carboniferous 

 strata, part of a belt of the same, stretching from the head waters of 

 the Liddel to the mouth of the Nith. The rocks here belong to the 

 Carboniferous limestone series between the true Coal-measures and 

 the Calciferous Sandstones, and exhibit some remarkable phenomena. 

 Granite, Silurian, Carboniferous sandstone, shale, limestone, ironstone, 

 coal, and trap, are seen in the course of a short walk along the shore; the 

 great variety of strike running in the shortest distance to every point 

 of the compass, and showing strange examples of curved stratification. 

 Great change in the dip of the rocks from horizontal to beyond perpen- 

 dicular; numberless and striking " troubles," slips, dykes, and fold- 

 ings ; all exhibited as in a seaside museum ready for the student. 

 Fossil corals may be collected, and whole beds of corals seen, with 

 their dome-shaped masses in natural position as they lived in the 

 Carboniferous sea. Eipple-marks, worm-castings, annelide-borings, 

 and footprints are also well shown on the exposed surfaces, A list 

 of the fossils found was given. Other geological phenomena were 

 also referred to, as sea-action in the formation of caves, stacks, and 



