572 Correspondence — E. J. Edwards. 



conditions of glaciatiou in the Isle of Man, where the highest 

 summit, over 2,000 feet above present sea-level, has been striated 

 transversely to the direction of the hill-range by ice which must 

 have risen considerably above the summit, while there is strong 

 evidence that the same ice-sheet filled up the adjacent basin, now 

 occupied by the Irish Sea, which was certainly in existence before 

 the glaciation. And indeed, since I know that this reviewer 

 accepts the 'laud-ice theory' for our glacial drifts he would find 

 no deai'th of instances where the geological evidence is incompatible 

 with the restriction supported by Professor Schwai'z. 



Furthermore, I have reason to believe that the reviewer gathered 

 from at least one physicist that the calculation in question would not 

 be trustworthy under the conditions of a moving ice-sheet. In 

 short, this reviewer and I are at one in concluding tliat the evidence 

 for the past and present existence of ice of greater thickness than 

 1,600 feet is so strong that the physicists who wish to apply this 

 limitation may be advised, in their own interest, to revise their 

 calculations. G. W. Lamplugh. 



Nottingham. 



November 7th, 1906. 



THE KEISLEY LIMESTONE. 



Sir, — While welcoming Dr. Marr's paper on the Keisley limestone, 

 in your November issue, as a most important addition to our 

 knowledge of that rock, I should like to point out a slight inaccuracy 

 repeated from his and Nicholson's previous paper on the Cross Fell 

 inlier — a mistake discovered several years ago while accompanying 

 Professor P. F. Kendall's field class in Westmorland. 



Dr. Marr says (quoting from the previous paper) — " at a point 

 where a tributary stream (Rundale Beck) enters Svvindale from the 

 east," etc. This should be Small Burn, and not Rundale Beck. 



His description of the Staiirocephalus limestone applies to the 

 beds below the junction of Small I3urn and Swindale Beck, while 

 around the junction of Rundale (or Great Rundale) Beck and 

 Svvindale Beck, about 220 yards further south, the Stockdale shales 

 are developed, into which a lamprophyro dyke is intruded, as shown 

 in the section on the map accompanying the paper on the Cross Fell 

 inlier. 



The streams are correctly named in the description of this area in 

 the Survey Memoir on " The Geology of Appleby, UUswater, and 

 Haweswater " (pp. 36 and 41). 



The names of tlie streams are taken from the 6-inch Ordnance 

 Map, and I take this opportunity of pointing out the mistake, so 

 that strangers to the district may not be misled by the wrong naming 

 of the stream, if they should ever wish to make a closer acquaintance 

 with this interesting bed in the field. E. J. Edwards. 



12, Norwood Terrace, Leeds. 

 November Sth, 1906. 



