24 NATURAL SCIENCE. July. 



the Green Muds, sulphide of iron in the Blue Muds, siliceous and 

 calcareous concretions in the calcareous deposits, and manganese- 

 iron nodules and zeolitic minerals (phillipsite) in the Red Clays. 



The following table, given by Messrs. Murray and Renard, 

 shows the mean depth, mean percentage of carbonate of lime, and 

 the estimated area of the various deep-sea deposits. 



Mean Depth in Mean Percentage Area, Square 

 Fathoms. of CaCOa. Miles. 



Red Clay 2,727 



Radiolarian Ooze .. .. .. 2,894 



Diatom Ooze .. .. .. i.477 



Globigerina Ooze .. .. .. 1,996 



Pteropod Ooze .. .. .. 1,118 



Coral Sands and Muds . . . . 710 



Other terrigenous deposits. Blue 



Muds, etc 1,016 



IV.— BOTANY. 



It is a pity that the " Challenger " staff did not, as was originally 

 suggested, include a botanist, qualified to observe and collect, who 

 might have devoted the whole of his time to his own subject. This is 

 no disparagement of the excellent services rendered by Moseley, whose 

 interesting notes supply some of the most readable and instructive 

 pages to the ponderous vol. i. on Botany. As Mr. Clarke points out, 

 this includes much more than the Botany of the " Challenger" Expedi- 

 tion. In it Mr. Hemsley has got together from many various sources 

 the facts relating to the history of insular floras, while, in the lists of 

 plants, the material of our national herbaria has been used, dating as 

 far back as some of the collections acquired by Sir Hans Sloane, now 

 one of the most cherished possessions of the British Museum. To the 

 Keeper of the Botanical Department in that Museum we are indebted 

 for the following notes on — 



The Marine Flora. 



The shore Algae collected by Moseley during the cruise of H.M.S. 

 " Challenger " were worked out by the late Professor Dickie, and 

 published in the journal of the Linnean Society as he received the 

 collections from different localities. Professor Dickie's herbarium, 

 now in the British Museum, was a good one, but not quite good 

 enough for the purpose of determining with accuracy collections from 

 so Avide an area as that covered by H.M.S. " Challenger," and the 

 result is that a number of the names do not stand. It was, 

 however, an excellent piece of work, and as well done as it could have 

 been outside the herbaria of the British Museum, Kew, or Dublin. 

 Not many new species were added, but we have learned from these 

 collections all we know of the marine flora of the small islets of the 

 Southern Ocean. The " Transit of Venus " Expedition to Kerguelen 

 Island added to our knowledge in that particular case. Considering 



