424 NATURAL SCIENCE. dec. 



It is evident to anyone of ordinary common sense in scientific 

 matters that such questions can only be answered — if they can be 

 answered — by appeal to facts ; unfortunately — or perhaps fortunately 

 — facts present themselves in different colours to different minds, and 

 what one looks upon as conclusive proof of the action of the sea, 

 another thinks points decisively towards land-ice. Let us, then, 

 shortly review what is known of these chameleon-like drifts, and try 

 to present the information in a way that each reasoner may have an 

 opportunity of forming his own conclusions — if, indeed, he feels equal 

 to the task of taking so much trouble. 



The first discovery of the high-level shelly drift in the British Isles 

 was made by Joshua Trimmer, and recorded in the Proceedings of the 

 Geological Society in 1831. It occurred on MoelTryfaen, Carnarvon- 

 shire, at a level of between 1,300 and 1,400 feet. 



There have been many discoveries in other localities since, but 

 MoelTryfaen remains classic ground, not alone on account of priority, 

 but because of certain features which differentiate it from the other 

 shelly-sands and gravels, of which I have given detailed descriptions 

 and illustrations in a monograph lately published by the Liverpool 

 Geological Society.^ The next discovery was made by the veteran 

 geologist, Mr. Joseph Prestwich, of a shelly patch near the Setter Dog, 

 between Macclesfield and Buxton, at a level of about 1,200 feet above 

 the sea. The Macclesfield Cemetery beds, at a level of about 600 

 feet — consisting mostly of shelly-sands some 70 feet thick — followed, 

 and were described by the late Dr. Sainter and Mr. R. D. Darbi- 

 shire.- Similar shelly-sands and gravels were discovered and de- 

 scribed in Flintshire at Halkin Mountain, and up to 1,000 at Moel y 

 Crio, by the late Daniel Mackintosh ; and between Minera and Llan- 

 gollen the same indefatigable observer, to whom Drift Geology owes 

 so much, found an extension of the same shelly drift at levels ranging 

 from 1,000 to 1,200 feet. Still more recently, these high-level shelly- 

 sands and gravels have been traced further south, and occur at 

 Gloppa, two miles from Oswestry, in great force up to the level of 

 1,200 feet above the sea, having a depth of 60 feet unbottomed. Mr. 

 A. C. Nicholson, F.G.S., has given an excellent description of these 

 beds 3 which, fortunately for geologists, he assiduously worked during 

 the whole of the excavations made in carrying out the works of the 

 new water-supply for Liverpool from the River Vyrnwy. Mean- 

 while, geologists in the Sister Isle were not idle, and the Rev. Maxwell 

 H. Close recorded the presence of a remarkable deposit of shelly- 

 gravels at BallyedmondufT on the Three-rock Mountain, near Dubhn, 

 at an elevation of over 1,200 feet,-^ and of other exposures at various 



1 The Drift Beds of the Moel Tryfaen Area of the North Wales Coast ; Session 

 1892-3. 



•^ Notes on Marine Shells found in the Stratified Drift near Macclesfield, by 

 R. D. Darbishire. Lit. & Phil. Soc. of Manchester, Session 1S64-5. 

 3 Q. J. Geo!. Soc, 1892. ^ Geo!. Mag., 1874. 



