336 Correspondence — R. Bullen Newton. 



importance of a structure which, when judged merely from its effects 

 on the surface rocks, appears to be of only minor importance. 



A further series of observations was carried out on the Jurassic 

 iron-ores of the Irthlingborough district of Northamptonshire. The 

 ores occur in the form of a nearly horizontal sheet of weakly 

 susceptible ferrous carbonate partly oxidized to hydrated oxides. 

 They give rise to small magnetic disturbances which are quite 

 capable o£ detection, and these may be of use in determining the 

 boundaries of the sheets in areas not affected by larger disturbances 

 of deep-seated origin. 



The results obtained by the joint magnetic and geological work in 

 the two areas show that this method of investigation may be used to 

 •extend our knowledge of the underground structure. It appears also 

 that an extension of the method to other parts of the country would 

 yield information of considerable scientific and economic importance. 



Geological maps were exhibited by Dr. A. Hubert Cox, M.Sc.,F.G.S., 

 in illustration of his lecture. 



00:RI?,E!SE'OITr)E]lSrCEl. 



EICHAED HALL. 



Sir, — Excellent notices have appeared recently in Nature and in 

 tlie Geologicai, Magazine calling attention to the important work 

 ^accomplished by Mr. Richard Hall, now retired, during his thirty- 

 eight years of service in the Geological Department of the British 

 Museum as a " preparer of fossils ". 



Sufficient stress has not been laid on Mr. Hall's skill in the 

 development of invertebrate fossils, also in the preparation of 

 delicate microscopic objects and the cutting and polishing of rock- 

 surfaces exhibiting organic structures. Special attention might be 

 called to the large sei'ies of sections of Monticuliporoid corals figured 

 and described by Dr. Foord, Mr. Robert Etheridge, jun., and the late 

 Professor H. A. Nicholson. 



He also made the large sections on glass of the Palaeozoic corals 

 now in the Geological Department, which enable the student to 

 study with ease the internal characters of tlie Cyathophylloid and 

 other groups. Later he prepared microscopic sections of Foraminiferal 

 rocks which proved of material assistance in researches in the geology 

 of Africa, Madagascar, New Guinea, Borneo, etc. It is a surprising 

 fact that an operator who could so successfully disentomb from its 

 matrix a great reptile like the Pariasaiirus should have been equally 

 proficient in the preparation of delicate sections of microscopic 

 objects. R. Bullen Newton. 



TvOIISCE! 3L.1L. .A-HSTE O XJS. 



Ludlow Museum. — We are glad to learn that the Ludlow Natural 

 History Society has received a bequest of £200 from the late 

 Mrs. Agnes Mary White, daughter of the well-known geologist, the 

 late Mr. Humphry Salwey, of The Cliff, Ludlow. It is a welcome 

 contribution to the funds of an important institution which has 

 suffered much from lack of means durinsr recent vears. — A. S. W. 



