42 Professor J. W. Gregory — Tlte Eiiglisli ''■ Eshers ". 



the Alyn valley, S.E. of Mold, where two eskers rise through the 

 alluvium, the most esker-like occurring between two tributaries 

 to the Alyn ; at Maes-y-groes in the upper Alyn Valley, about 

 3 miles W. by N. from Mold ; and at Sarn Mill and at Groessffordd, 

 in the valley of the Chwyler. The low level eskers appear to be all 

 denuded remnants of a sheet of sand and gravel interstratified 

 between two boulder clays. They are usually ridge-like because 

 they are due to denudation along the valleys. It is worthy of notice 

 that these gravels are near the line marked by Sir A. Strahan as 

 the margin of the North Welsh ice. 



2. Anglesey. — Mr. Greenly has described a series of " eskers " in 

 Anglesey .1 From his account they appear to be fiuvioglacial in 

 origin, and to be restricted to low levels on the margins of the island, 

 ranging in level from 100-239 feet. 



3. Central Wales. — A ridge 120 feet high of stratified false- 

 bedded glacial gravel, sand, and clay across the Ystwyth Valley, at 

 Llanrhystyd Eoad Station, S.E. of Aberystwyth, has been described 

 as an esker by W. Keeping.^ He refers to its aspect as like that of 

 moraines, but says " its structure is totally different ". The pebbles 

 are " so little waterworn " that they retain glacial striae and are 

 subangular. It appears to be part oi a bar deposited on the front 

 of the ice sheet that descended the Ystwyth valley ; as seen from the 

 railway, which exhibits a good section through it, the formation is 

 kanie-like in aspect ; Keeping's excellent account of this formation 

 indicates that it is a glacieluvial kame, formed, as he remarks, where 

 the Ystwyth valley opens out to a plain near the sea. 



4. 8. Wales. — Sir A. Strahan has described some of the gravel hills 

 near Abergavenny and Newport as eskers.^ They appear to be 

 residual hills due to the denudation of the great sheet of fiuvio- 

 glacial gravel which was deposited in the Usk Valley along the 

 S.E. edge of the S. Wales glaciers. 



XI. The Distribution and Classification of the English 

 Kames, Eskers, and Osar. 

 From the evidence in the foregoing summary the English " eskers " 

 may be classified as follows : — 

 Osar : Kingswinford and Newport, Salop. 

 Kames : — 



Fiuvioglacial : Bingley ; Panton ; Blakeney ; Anglesey ; 



S. E. Northumberland. 

 Glacieluvial : Lucker ; Elsdon ; Kellet Bridge, near Carnforth ; 



Llanrhystyd. 

 Eesidual : Wark ; Bowmont Water ; W. Durham ; Durham 

 City ; Hunstanton ; Usk Valley, 



1 Mem. Geol. Szirv., Anglesey, 1919, vol. ii, pp. 706, 725, 730, 741, 749-50, 

 759, 762. 



2 Geol. Mag., 1878, p. 541 ; 1882, p. 256. 



3 Mem. Geol. Siirv., S.W. Coalfield, ii, 1900, pp. 89-90 ; Newport, 249, 1899, 

 pp. 81-2. 



