54 Mr. De la Becke on [Jutv; 



expenments with that instrument, whith vvas an unhoped-for 

 accession to its powers. 



Pr» J^laqk mentioned to me its having been used by an 

 assayer ;n Cornwall, to whom he had made it known ; and I 

 have since heard, from another person, of an assayer in that 

 county, who, finding the assays he was employed to make, cost 

 him more in fuel than he was paid for them, had contrived means 

 of making them at the blowpipe on one grain of matter. I pre- 

 sume him to have been the same Dr. Black had spoken of. 



London f Majf 12, 18S6. 



Article IX. ..^,. 



Notice on the Diluvium of Jamaica, 'By^H. T. De la Beche, 

 FRS. &c. (Read at the Bristol Philosophical Society, 

 May 12, 1825.) 



Any addition to our information respecting diluvium cannot 

 be without interest to geologists, more particularly when it is 

 derived fi*om countries far distant from those which have been 

 previously examined. Prof. Buckland's distinctions between 

 diluvium and alluvium are too well known to require any expla- 

 nation. That objections have been raised to these distinctions, 

 and the discoveries connected with them, is most certain ; but 

 as Prof. Sedgwick very justly observes {Annals of Philosophy, 

 April, 1825), " the greater part of the objectors are undeserving 

 of any animadversion, as they appear entirely ignorant of the very 

 elements of geology, and far too imperfectly acquainted with the 

 facts about which they write to have it in their power to turn 

 them to any account." In this class may not unfairly be placed 

 the work which a writer in the Quarterly Journal of Science very 

 gravely informs us is masterly ! ! 



The following observations were made during a residence in 

 the Island of Jamaica from December, 1823, to December, 1824. 

 The first district which I shall notice is the great plain of 

 Liguanea, upon the lower part of which the city of Kingston is 

 situated. This presents an inclined surface, falling gradually 

 from a height of about 750 feet (where the plain abuts against 

 the mountains bounding it on the N) to the sea. This plain is 

 almost wholly composed of diluvial gravel, consisting of the 

 detritus of the Jamaica mountains, and evidently pyqduced by 

 causes not now in action. .^.jg ^r j ., 



