II. 



Deep-Sea Deposits.- A Review of the Work of 

 the " Challenger " Expedition.' 



THE long-expected report by Messrs, Murray and Renard on 

 the deep-sea deposits collected during the cruise of the 

 ."Challenger," has made its appearance, and will be cordially 

 welcomed by all geologists. Many of the facts and most of the 

 conclusions have been published in the proceedings of various 

 societies, and have even found their way into text-books. Neverthe- 

 less, it is to this volume that all those who are desirous of studying 

 the geological operations at present going on in our great ocean 

 basins will necessarily turn. 



The work forms a bulky quarto volume of five hundred pages. 

 It is illustrated by forty-three charts indicating the positions of the 

 sounding and dredging stations, a coloured map of the world repre- 

 senting the distribution of the principal deposits, twenty-two 

 diagrams showing the vertical distribution of temperature and the 

 relations between the deposits and depth, thirty-six woodcuts, and 

 twenty-nine lithographic and chromolithographic plates, many of 

 which are beautifully executed and give an excellent idea of the 

 objects they represent. 



The deposits were examined in the following way. The 

 proportion of carbonate of lime was approximately ascertained in 

 each case by the direct determination of carbonic acid. The relative 

 amount of the remains of the different hme-secreting organisms was 

 roughly estimated by microscopic examination. The residue in the 

 carbonic acid apparatus was then separated into three parts — siliceous 

 organisms, minerals, and fine washings — by fractional decantation, 

 and the relative proportions of these three constituents also estimated. 

 The percentage composition of each deposit is given in terms of 

 (i) pelagic foraminifera, (2) bottom-living foraminifera, (3) other 

 calcareous organisms, (4) siliceous organisms, (5) minerals, and (6) 

 fine washings. Under the last head are included argillaceous 

 material, organic matter, minute fragments of siliceous organisms,, 



1 Report on Deep-Sea Deposits Based on the Specimens Collectei> 



DURING THE VOYAGE OF H.M.S. " CHALLENGER." By JOHN MURRAY, LL.D., 



Ph.D., and Rev. A. F. Renard, LL.D., Ph.D. London: Eyre and Spottiswoode. 

 1891. 



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