Geological Society. 367 



of Moel Tryfane. It is stated, by this author, that gravel, sand, and 

 cluy are heaped up, not only in the valleys, but on the sloping sides 

 and summits of the hills, and that the transported materials consist of 

 pebbles and blocks of Caernarvonshire rocks, mixed up with other de- 

 tritus, derived from formations foreign to this district, and drifted in a 

 direction contrary to the courses of the rivers which now descend 

 from Snowdonia. Mr. Trimmer discovered on the summit of Moel 

 Tryfane, one thousand feet above the level of the sea, broken shells 

 of recent species of the genera Buccinum, Venus, Natica, and 

 Turbo, beneath twenty feet of sand and gravel. The same shells have 

 also been seen by him, in similar accumulations, in the low cliffs of 

 Beaumaris. It is likewise mentioned that the slate-rock, when laid 

 bare, frequently exhibits on its surface, scratches and furrows, like 

 those wliich have been described in Scotland. 



This striking phsenomenon, of the sea having overspread the western 

 parts of this island at a period so comparatively recent, led me in a 

 late journey along the north-west coast, to endeavour to ascertain 

 whether the lower country of Lancashire had partaken of similar 

 operations ; and I was induced to suppose this might have been the 

 case from the occurrence, as stated by Mr. Gilbertson, of marine shells 

 of existing species near Preston in Lancashire. 1 was fortunately 

 able to confirm this discovery ; and to observe similar phaenomena 

 over a very considerable tract of country, occupying the ancient 

 estuary of the Ribble. Sands, marls, and gravels, occasionally 

 constituting terraces, are spread over this great area, sometimes in 

 finely laminated beds, but for the most part loosely aggregated, and 

 bearing a great resemblance to the arrangement of the same materials, 

 now in the act of formation, on the adjoining shore. Many of the 

 shells found in these beds, far inland and at heights extending to 

 three hundred feet above the sea, are perfectly identical with existing 

 species. These circumstances have induced me to dissent from the 

 theory, which would refer all these deposits to a diluvial current ; and 

 1 have inferred, that the ancient shore of Lancashire, and the es- 

 tuary of the Ribble, in which the above materials had accumulated 

 during a long protracted epoch, were elevated and laid dry after the 

 creation of many of the existing species of mollusca. 



Of communications descriptive of foreign countries, 1 have first to 

 notice two papers by Fellows of this Society on different parts of 

 distant colonies in Australia. One of them by Archdeacon Scott, 

 accompanied by instructive specimens, is interesting, as being 

 the first attempt at a geological sketch of the country around 

 the new settlement of Swan River. This tract, we are told, has 

 a granitic nucleus, which towards the coast is overlaid by sandstone 

 and limestone ; these being succeeded along the shore by coralline 

 and shelly deposits of very modern date. — The other memoir, from 

 the pen of Major Mitchell*, Surveyor-General of New South Wales, 



gives 



• The aiithorof this memoir, who acquired such deserved scientific rc()u- 

 tation in the peninsular war hy his beautiful military (innvinfjs of the Pyre- 

 nees, has lately annoiuiced to me his completion of tiie Trigonometrical 

 Survcv of an im[)Grtant part of our eastern colonies in Australia ; after 



the 



