Correspondence — A. Strahan — T. G. Bonnet/. 287 



I have traced the Interglacials, as gravel, sand, and muddy sand- 

 beds, in the Bowbrone, Garpel, and Guelt valleys, to an altitude of 

 900 feet above sea-level. The shell-beds occur in the parishes 

 of Loudoun, Sorn, Auchenleck, and Colmonell. The Interglacials 

 range from Dairy to Colmonell, and inland to Muirkirk. 



John Smith. 



MONKREDDING, KlLWINNING. 



April 29th, 1896. 



AMMONITES (ACANTHOCERAS) MAMMILLATUM IN THE 

 ISLE OF WIGHT. 



Sir, — In the Geological Magazine for May, 1896, p. 199 

 (footnote 2), Mr. R. B. Newton calls attention to Ammonites mam- 

 millatum having been recorded from the Chloritic Marl in the 

 Geological Survey Memoir on the Isle of Wight, second edition, 

 p. 279, and suggests that there is a mistake. In this I think he 

 is probably right. The table in the Memoir was drawn up in such 

 a way as to show the authority for every fossil. A. mammillatnm 

 was inserted on the authority of Captain Ibbetson ("Note on the 

 Geology and Chemical Composition of the various Strata in the Isle 

 of Wight," 1849, p. 22), who quotes A. monile from the Chloritic 

 Marl. A. monile, Sow., according to D'Orbigny (Pal. Franc. Terr. 

 Cret. 1840-1, p. 249), Bronn (Index Pal. 1848, p. 51), and 

 Morris (Cat. Brit. Foss. 1854, p. 297), is A. rnammillatum, Schloth. 

 The mistake probably lay in the determination of Ibbetson's speci- 

 men as A. monile. A Strahan. 



12, Marloes Road, Kensington, W. 



ICE-WORK. 



Sir, — The author of the excellent summary of my book on Ice- 

 Work (see Geol. Mag. for last month, pp. 228-231) seems to have 

 misunderstood me in one respect. In regard to the parallel roads 

 of Glenroy, he states — " the objections to a marine origin for these 

 'roads' are regarded as insuperable." I think that a comparison of 

 pages 94-107 with pages 163-198, will show that this is not my 

 opinion. Indeed, I have more than once maintained the contrary. 

 I venture on this correction lest I should be supposed to have 

 changed my mind. 



23, Denning Road, Hampstead, N.W. T. G. BoNNEY. 



May IGth, 1896. 



nvniSCZELXj^ZLsTIEOTT; 



Guide to the Museum of Practical Geology. — The "Descrip- 

 tive Guide " to this Museum, of which a fourth edition was published 

 in 1877, has long been out of print, and a new edition has been 



