506 FLORA ANTARCTICA. \Fuegia, the 



Again, some of the Antarctic species have been detected floating in the atmosphere which overhangs the wide 

 ocean between Africa and America. The knowledge of this marvellous fact we owe to Mr. Darwin, who, when he 

 was at sea near the Cape de Verd Islands, collected an impalpable powder which fell on Captain Fitzroy's ships. 

 He transmitted this dust to Elirenberg, who ascertained it to consist of the siliceous coats, chiefly of American 

 Dialomacece, which were being wafted through the upper regions of the air, when some meteorological phenomenon 

 checked them in their course, and deposited them on the ship and surface of the ocean. 



The existence of the remains of many species of this Order (and amongst them some Antarctic ones), in the 

 volcanic ashes, pumice, and scoriee of active and extinct volcanoes (those of the Mediterranean Sea and Ascension 

 Island for instance), is a fact bearing immediately upon the present subject. Mount Erebus, a volcano 12,400 

 feet high, of the first class in dimensions and energetic action, rises at once from the ocean, in the 78th degree of 

 south latitude, and abreast of the Diatomacece bank, which reposes in part on its base. Hence it may not appear 

 preposterous to conclude, that, as Vesuvius receives the waters of the Mediterranean, with its fish, to eject them by 

 its crater"; so the subterranean and subaqueous forces which maintain Mount Erebus in activity, may occasionally 

 receive organic matter from this bank, and disgorge it, together with those volcanic products, ashes and pumice. 



Along the shores of Graham's Land and the South Shetland Islands, we have a parallel combination of igneous 

 and aqueous action, accompanied with an equally copious supply of Diatomacece. In the Gulf of Erebus and Terror, 

 15 degrees north of Victoria Land, and placed in the opposite side of the globe, the soundings were of a similar 

 nature with those of Victoria Land and Barrier, and the sea and ice as full of Diatomacece. This was not only 

 proved by the deep-sea lead, but by the examination of bergs, which, once stranded, had floated off and become 

 reversed, exposing an accumulation of white friable mud, frozen to their bases, which abounded with these vegetable 

 remains. 



The following systematically arranged catalogue of the hitherto described Antarctic species is drawn up from 

 various papers by Professor Ehrenberg, but principally from that which appeared in the ' Monatsberichten der 

 Berliner Akad. der Wissenschaften " for May, 1841, and which has been reprinted in Taylor's 'Annals of Natural 

 History ', and in the Appendix of Sir James Ross' ' Narrative of the Antarctic Expedition '. A few Falkland 

 Island and Kerguelen's Land species have subsequently been examined by Mr. Thwaites, to whom, and to the 

 Rev. Mr. Berkeley, I am much indebted for the assistance they have afforded me in this group. The arrangement 

 of the genera followed is that of M. Kiitzing's great work on this order. 



1. EUNOTIA, Ehrb. 



1. Eunotia gibberula, Ehrb. Epithemia gibberula, Kiits. Kieselsck. Bacill. p. 35. t. 29. f. 54, c. 



Hab. Open Ocean, in Pancake-ice, Lat. 75° S. Long. 170° W. 



An inhabitant of the Baltic Sea. Found fossil at Newhaven, in Connecticut, in volcanic ashes from the Rhine 

 and amongst an atmospheric dust which fell near the Cape de Verd Islands. 



2. Eunotia amphioxys, Ehrb. Kiitz. 1. c. p. 44. t. 30. f. 1. 



Hab. Falkland Islands, Lesson. Cockburn Island, amongst the guano of a Penguin rookery. 



surface of the barrier, in a climate where there is no thaw throughout the year, and where snow lies perennially, 

 will result in the sinking of the barrier and its base becoming imbedded in this stratum of vegetable debris. 

 Supposing the barrier, then, to have a progressive motion, such as smaller but similar glaciers exhibit, the result 

 would be flexures of the pasty stratum of mud upon whose edge it rests, and against whose walls it would in time 

 abut, as the deposit thickens. 



