228 Notices of Memoirs — Prof. Prestwich — 



some possible moraines, of the second glacial period, or the times 

 next preceding and following it ? Surely there ought to be such if 

 the land has not been submerged since. 



I would take this opportunity of correcting an error of the press 

 in my previous paper. In the diagrams, p. 83, for " Account of the 

 Isle of Man," read " Antiquity of Man ;" also, for Turby read Jurby, 

 pp. 84 and 85. 



In reply to Mr. Kinahan's letter in the April Number of the 

 Geological Magazine, I may be allowed to say that he seems to 

 assume tbat I had seen the deposits to which he refers, and had been 

 writing from personal observation. In this he is mistaken, as I have 

 never been in Ireland. In alluding to the order of the Irish glacial' 

 series, I relied solely on the authority of Professor Hull's paper. 1 



Mr. Kinahan dissents : and says that an Upper Glacial Drift 

 (Boulder-clay) has not been proved to exist in Ireland ; but it is 

 clear that he says so on the ground of a different definition of Glacial 

 Drift, implied if not expressed, according to which it is never found 

 stratified or rearranged ,: 2 whereas according to the views expressed 

 in the paper above referred to, being "generally marine," 3 it would 

 naturally often occur under both conditions. 



UOTICES OIF 1 ZMZZEDVUOIIRS- 



I. — On the Origin of the Chesil Bank, and on the Belation op 

 the Existing Beaches to past Geological Changes, inde- 

 pendent OF THE PRESENT COAST ACTION. 4 

 By Professor Joseph Prestwich, M.A., F.E.S., V.P.G.S., Assoc. Inst. C.E. 



THIS remarkable bank of pebbles, extending from Portland to 

 Abbotsbury, a distance of nearly 11 miles, was described with 

 great accuracy by Sir John Coode, M. Inst. C.E., in 1853 (vide 

 "Minutes of Proceedings Inst. C.E.," vol. xii. page 520). 5 It was 

 then 43 feet high and 600 feet wide at the south end, decreasing to 

 23 feet high and 510 feet wide at the north end. The pebbles 

 diminished in size from Portland to Abbotsbury. Sir John Coode 

 also stated that the shingle consisted chiefly of pebbles of chalk-flint, 

 with a small proportion of others of red sandstone, porphyry and 

 jasper, none of which could have been derived from local rocks. In 

 order to determine their origin, he examined the coast from Port- 

 land to Start Point, and traced the flints to the chalk cliffs between 

 Axmouth and Lyme, and the red sandstone, porphyry, and jasper 

 pebbles to the New Bed Sandstone of Budleigh Salterton, and other 

 places in Devonshire; whence he concluded that the only source 



1 Geol. Mag. July, 1871, pp. 294 sq. 



2 Geol. Mag. April, 1874, p. 171, and April, 1875, p. 189. 



3 Geol. Mag. July, 1871, p. 299. 



4 Being the substance of a paper read at the Tenth Ordinary Meeting of the 

 Institution of Civil Engineers held on Tuesday evening, the 2nd of February, 1875. 



5 See also a valuable paper on the Chesil Bank by Messrs. H. ~W. Bristow, F.E.S., 

 and W. Whitaker, B.A., F.G.S., in Geol. Mag., 1869, Vol. VI. PI. XIV. and XV. 

 page 433. 



