



Dr. Hooker's Flora Antarctica. 177 



their vegetable nature. Following the high authority of Ehren- 

 berg, Dr. Hooker had supposed the Diatomacea? to pertain to the 

 animal kingdom, and consequently had supposed all vegetation to 

 cease at a much lower latitude than these productions attain. He 

 collected them, however, on every available occasion during the 

 voyage, and on his return transmitted them to Prof. Ehrenberg, 

 whose determination of the genera and species is introduced into 

 the Flora Antarctica, where they find a place as a distinct order 

 of plants. The circumstances under which they occur, and the 

 modes in which they were collected and preserved for examina- 

 tion are thus described. 



" The waters and the ice of the South Polar Ocean were alike 

 found to abound with microscopic vegetables belonging to this 

 order. Though much too small to be discernible by the naked 

 eye, they occurred in such countless myriads as to stain the berg 

 and the pack-ice, wherever they were washed by the swell of the 

 sea ; and when enclosed in the congealing surface of the water, 

 they imparted to the brash and pancake ice a pale ochreous color- 

 In the open sea northward of the Frozen zone, this order, though 

 uo doubt almost universally present, generally eludes the search 

 of the naturalist ; except when its species are congregated amongst 

 that mucous scum, which is sometimes seen floating on the 

 waves, and of whose real nature we are ignorant ; or when the 

 colored contents of the marine animals who feed on these Algae 

 are examined. To the south, however, of the belt of ice which 

 encircles the globe, between the parallels of 50° and 70° S., and 

 in the waters comprised between that belt and the highest lati- 

 tude ever attained by man, this vegetation is very conspicuous, 

 from the contrast between its color and the white snow and ice in 

 which it is imbedded. Insomuch that, in the 80th degree all the 

 surface ice carried along by the currents, the sides of every berg, 

 and the base of the great Victoria Barrier itself, within reach oJ 

 the swells, were tinged brown, as if the polar waters were charged 

 with oxyd of iron. 



"As the majority of these plants consist of very simple vegeta- 

 ble cells, enclosed in indestructible silex (as other Algae are in 

 carbonate of lime), it is obvious that the death and decomposition 

 of such multitudes must form sedimentary deposits, proportionate 

 "> their extent to the length and exposure of the coast against 

 which they are washed, in thickness, to the power of such agents 

 as the winds, currents, and sea, which sweeps them more ener- 

 getically to certain positions, and in purity, to the depth of the 

 water and the nature of the bottom. Hence we detected their 

 remains along every ice-bound shore, in the depth of the adja- 

 cent ocean, between eighty and one hundred fathoms. OlF Vic- 

 toria Barrier (a perpendicular wall of ice, between one and two 

 hundred feet above the level of the sea) the bottom of the ocean 



Second Series, Vol. VIII, No. 23.— Sept, 1849. 23 



