Mr. Moore on the Rocks of the Bay of Loch Ryan. 219 



Cilfay hill and the Town-hill range from Swansea to the Bury river, 

 there occur many irregular conglomerate beds, formed of innume- 

 rable pebbles and small boulders of coal, sometimes four inches in 

 diameter, mingled with sand and pebbles of ironstone ; and there 

 have been also found in them small boulders of granite and mica- 

 slate. Many impressions, coated with coal, of Sigillarise and other 

 plants, occur in the mass ; and the difference of age between this coal 

 and that of the pebbles, he says, is beautifully illustrated in numerous 

 cases, where the softer coal of the plants has been pressed down 

 upon the harder coal of a laj^er of the pebbles, by the cleavage of 

 the former, however distorted the plant may be, presenting an uni- 

 form parallelism, while the cleavage of the coal forming the pebbles 

 is parallel with the sides of the pebbles, which are inclined in all 

 possible directions. 



The pebbles consist principally of the common bituminous coal of 

 the neighbourhood, but two have been found composed of cannel 

 coal, the only seams of which, existing in the lower measures, occur 

 about 2000 feet below the conglomerate bed. 



The Cilfay sandstones and the measures at Penclawdd, in which 

 the first-mentioned pebble was found, form part of the Pennant grit ; 

 and there is reason to believe, that throughout the whole of this 

 great mass of sandstone, about 3000 feet thick, occasional beds of 

 coal pebbles are to be met with : but Mr. Logan has not seen any 

 associated with the lower measures. 



March 11, 1840 — A paper was first read, "On the Rocks which 

 form the West shore of the Bay of Loch Ryan in Wigtonshire, N.B.," 

 by John Carrick Moore, Esq. F.G.S. 



The peninsula of the Ryans extends about thirty miles from N. 

 to S., and is about seven miles across at its greatest breadth, or from 

 Stranraer to Port Patrick. In the geological maps of M. Necker, 

 Dr. Macculloch, and Mr. John Phillips, it is coloured as part of the 

 great graywacke chain, stretching from the Irish sea to St. Abb's 

 Head ; and the chief part of the rocks composing the peninsula, Mr. 

 Moore says, undoubtedly belongs to tliat epoch ; but he has ascer- 

 tained from an examination of the district during the summer of 

 1839, that others of a more recent date also exist. 



The portion of the peninsula particularly described by the author, 

 extends about eleven miles from north to south, and about five from 

 east to west ; and is bounded on the W. and N. by the Irish sea, and 

 on the E. by the Bay of Loch Ryan. The formations of which it 

 consists are — 1 . Graywacke, 2. Trap rocks, 3. Coal measures, and, 

 4-. a red breccia. 



1 . The graywacke constitutes the greater part of the district, the 

 beds being nearly vertical and the prevailing strike E. by N. At 

 the northern extremity, near the Corsewall Lighthouse, are beds 

 of conglomerate comjjosed of rounded masses of granite, with peb- 

 bles of serpentine and other rocks. In the little bay of Sloughna- 

 garry, at the most southern jjoiiit, where the graywacke shows itself, 

 Mr. Moore found in a slaty rock alternating with compact beds, an 

 abundance of fossils, determined by Mr. Lyell to be graptolites. 



