208 [Proc. B.N.F.C, 



Antrim have been recorded. A few I picked up at random are 

 on the table, amongst them you will find granite from Eskdale, 

 quartz-porphyry with riebeckite from Mynydd Mawr, Welsh 

 ophitic diabase, and a granitoid rock, probably Welsh Archaean. 

 For the sources of these I am indebted to Percy F. Kendall, 

 F.G.S. Thus the marine origin of these shelly sands and 

 gravels, sections of which have been found on Moel Tryfaen 

 from 1,170 to nearly 1,400 feet above the level of the sea, 

 seems undoubted. 1st. We have the shells and shell frag- 

 ments. 2nd. The foraminifera. 3rd. The extremely rounded 

 and polished grains of sand. 4th. The water- worn foreign 

 boulders. But the question how have they been deposited in 

 this unique position is one over which many contests have 

 been fought in the past, and which conflicting theories still 

 assail in the present. 



Joshua Trimmer, in accordance with the views of his time, 

 brought in diluvial currents as the explanation. Darwin, 

 eleven years later, recognised in the shattered and contorted 

 slate rock the effects of icebergs grating over the surface. The 

 late Sir Andrew Ramsay also attributed much of the glacial 

 phenomena of the district to floating ice, and from the con- 

 sideration of this high-level shell-bed and those of Macclesfield 

 and Ffridd Brynmawr, likewise associated with glacial material, 

 he inferred a submergence of the land to a depth of not less 

 than from 1,200 to 1,500 feet. In corroboration of this depth, 

 he cited the high-level, shell-bearing Pleistocene gravels of 

 Three Rock Mountain, near Dublin, ground rendered classic 

 through the researches of a geologist we all revere, the Rev. 

 Maxwell Close. 



A newer school of glacial geologists has since arisen who, 

 while admitting a submergence of 100 to 150 feet, maintain 

 that the glacial deposits of Great Britain are the results of 

 glaciers or ice sheets, and that wherever marine shells occur in 

 such deposits at high levels it can be proved from other evidence 

 that the ice advanced upon the land from the sea. Some of 

 the contents of the beds would thus be the relics of great shell 



