174 Revieics— Harrison^ s Goldfields of British Guiana. 



names, with an index of localities and a subject-index, the references 

 including such as were omitted from Bulletin No. 10, and, as far as 

 possible, all papers and books since published up to the end of 1904. 

 Eoth bulletins have been compiled by Senor Rafael Aguilar y Santillan. 

 As showing how complete the bibliography is, it may be mentioned 

 that the references to Popocatepetl in Bulletin No. 10 are 28 and in 

 Bulletin No. 17 as many as 72 in number; to Meteorites 55 and 208 

 respectively. 



B. HoBsoN. 



E, E ^V I El 'W S 



I. — The Geology ok the Goldfields of British Guiana. By 

 J. B. Hakrison-, M.A., C.M.G. Published by the direction of 

 the Governor of British Guiana. London: Dulau & Co., 1908. 



IT is nearly five and thirty years since the last Government lleport 

 on the Geology of British Guiana, that of Brown and Sawkins, 

 saw the light. Comparing that report with Mr. Harrison's work 

 one cannot fail to be struck with the great progress which gold-mining 

 has made in the colony, and the still greater advance in the methods 

 of geological science as applied to the problems of metamorphic 

 rocks and the genesis of ore deposits. We miss, perhaps, that spice 

 of adventure and. exploration which makes the older book so readable, 

 but in return we gain much solid knowledge of the complex 

 geological structure presented by this vast extent of little explored 

 country. The book, it may at once be said, is meant for the 

 geologist and the mining engineer rather than for the prospector, 

 though the route details and mining regulations which it includes 

 will be of use even for the latter class of readers. 



The colony is divided naturally into three regions. There is 

 a narrow coastal belt of alluvium, much of which is below high- water 

 mark, and was reclaimed partly by the efforts of the early Dutch 

 settlers by means of an elaborate system of dykes. Practically all 

 the rice, cotton, sugar, and rum, which are the staple products of 

 the country, are raised on these flat lands. Behind them are forest- 

 clad plains and grassy downs, where here and there the live rock 

 peeps out from beneath a dense covering (sometimes 200 feet 

 thick) of rotted rock and lateritic surface deposits. The great 

 hinterland, which makes up eleven-twelfths of the area of the 

 colony, consists of forest-covered ranges of elevated hills and flat- 

 topped, terraced, sandstone mountains. 



During the eighteenth century the Dutch were aware of the 

 occurrence of gold in a few spots, and Sir E. Schomburg was able 

 to confirm this by his explorations, but Brown and Sawkins saw 

 little of it, and it was only about the year 1886 that the discovery 

 of some rich placers on the Cuyuni and Essequibo Rivers started 

 a temporary boom. Since then the industry has gone ahead, over 

 seven millions of pounds worth of gold having been extracted within 

 the last twenty years, and it is to be expected that when the 

 latest methods of hydraulicking and dredging are brought to bear 



