524 Correspondence — T. Crook. 



the ponds oa Mill Hill and the high ground of Totteridge, which 

 have a very restricted drainage-area, and must owe their replenishment 

 to the same cause as the dew-ponds of the South Downs. 



7. Land Forms. — Another important communication, hearing on 

 Geology and Geography has been brought before the Geographical 

 Society by Professor W. M. Davis {Geographical Journal, September, 

 1909). He has, in a discourse on "The Systematic Description of 

 Land Forms ", sought to persuade geographers to introduce concise 

 methods of description and to employ precise terms for types of 

 feature. For this purpose a knowledge of geological structure as 

 well as the forces of erosion is necessary. 



8. A New Juhassic Ammonite. — A description of a new species of 

 Ammonite, of the genus Stepheoceras, was contributed by the late 

 Dr. J. F. Whiteaves to The Ottawa Naturalist (May, 1909). The 

 specimen was obtained from rocks, presumably of Jurassic age, in the 

 Nicola Yalley, British Columbia. 



9. Tin Deposits in the Malay Peninsula. — In a paper on "The 

 Origin of Tin Deposits", read by Mr. J. B. Scrivenor, before the 

 Perak Chamber of Mines, 1909, the author concluded that the tin 

 deposits in the Malay Peninsula conform with tin deposits elsewhere 

 in having as their source a mass of igneous rock containing a high 

 percentage of silica. The importance of fluorine as a reagent in the 

 processes that led to the formation of cassiterite was emphasized, while, 

 on the other hand, it appeared that boron was not essential in those 

 reactions. 



10. Tin Mining and Water Supply, Federated Malay States. — We 

 have received the Annual Beport for 1908, of Mr. Scrivenor, Geologist 

 to the Federated Malay States. He deals with the question of water 

 supply, and with the expectation that at a depth beneath the alluvial 

 mangrove mud of the Perak Biver there might be found sand saturated 

 by springs from the bed-rock of the valley. A trial-bore at Bagan 

 Datoh has, however, encountered brackish water at a depth of 

 150 feet. The tin-mining receives special attention, and the Lahat 

 ' pipe ' is described as an instance of a lode-deposit which is being 

 converted in situ into a detrital-deposit. The alluvial ore-deposits 

 are likewise dealt with. 



c oi?,:E?,ESE^03sriDE:isrcE. 



ON THE USE OF THE TERM 'LATEEITE'. 

 Sir, — In the September number of the Geological Magazine, p. 431, 

 Mr. J. B. Scrivenor has written objecting to the restricted and clefinite 

 use of the term laterite as advocated in the Bulletin of the Imperial 

 Listitute, 1909, vol. vii, p. 134. Mr. Scrivenor claims that the word 

 laterite "has been used in the Malay Peninsula for many years by 

 a large body of engineers for what are essentially masses of iron oxide 

 replacing portions of weathered rocks, and filling fissures in such 

 rocks near the surface". He also claims that "laterite is an 

 engineer's rather than a geologist's term, covering rocks of varying 



