ii PROCEEDINGS OF THE GEOLOGICAL SOCIETY. lVoI. Ixxiil, 



had been collected during the last six months from near the top of 

 a section of cuiTent-bedded and faulted Glacial Sand and Gravel 

 at an altitude of about 200 feet O.D. 



The pebbles occm* in situ some 2 or 3 feet below the capping of 

 darker subsoil, which contains cores and flakes of flint, including 

 pigmies. They consist of slate, gi-anites (Eskdale and Shap), 

 Ennerdale granophvre, Borrowdale volcanic tuffs, porphyries, 

 quartzites. Millstone Grit, sandstones, Chalk flints. Carboniferous 

 chert, and other rocks. 



Tlie largest facetted pebble measures 11^ x 8| inches, and is 

 7 inches high ; the smallest is only half an inch in diameter. 



The facets are generally concave, grooved, or fluted. They vary 

 in number : some stones have one facet only, others t^vo or more. 

 One stone with a flat top shows five incipient facets. On some 

 the grooving is of the nature of parallel series of elongated pits. 



Differentiation, according to varying hardness and composition, 

 is well displayed on the granites, porphyries, grits, etc., where the 

 weaker constituents have been strongly eroded, leaving the stones 

 witli an irregularly pitted surface. 



The production of facets by splitting along joint-planes is seen 

 on some examples of sandstone ; but the facet thus formed has 

 been modified by wind-action. 



A few pebbles occurred in the sand completely inverted, and 

 show some distinct facetting on both sides. 



Of examples orientated in situ, the facets faced north-westwards, 

 westwards, and south-westwards — the directions of the present 

 prevailing winds. 



All the pebbles are of Glacial origin, but the facetting may be 

 relatively quit€ recent. The upper part of the sands where they 

 occur may be the result of redistribution by wind before a soil-cap 

 began to form. 



A series of pohshed specimens of Palaeozoic corals was exhibited 

 bv W. F. Gwinnell, B.Sc, F.G.S. 



"a geological map of British Guiana, 1913 (1:633,600, or 

 1 inch = 10 miles), presented by the Secretary of State for the 

 Colonies ; and twelve sheets of maps published and presented by 

 the Geological Survey of Japan, 1916 (1 : 400,000), were also ex- 

 hibited. 



Numerous books and pamphlets from the Library of R. D. 

 Oldham. F.R.S., V.P.G.S., were exhibited. These formed a selection 

 of an extensive series of publications, relating chiefly to seismology, 

 that Mr. Oldham recently presented to the Society. 



