REPOKT ON THE DEEP-SEA DEPOSITS. 
XXI 
multitude of shells belonging to very small marine animals, then considered as nautili 
and ammonites — an error which lasted till 1835. As he assigned no particular names to 
the diverse forms, which he described and figured with care, and even grouped according 
to certain analogies, Soldani did not advance the knowledge of them as much as he might 
have done had he applied the then well-known nomenclature of Linnaeus. In 1789-1797 
he produced another very considerable work ^ on the microscopic shells found on the 
shores of the islands of Giglio, Elba, Massa, &c. He observes in this work that these 
small bodies are not young specimens which grow with age, but are perfect adults. The 
various species occupy various depths, and this explains, he adds, why those in a fossil 
state are not found mixed indifferently in all the strata. 
In 1836 Professor C. G. Ehrenberg produced his first works. His name will ever 
remain inseparably connected with the discoveries relating to the microscopic organisms of 
the sea. It would be impossible to enumerate here the numerous memoirs and important 
publications of this micrographer, who devoted his whole life, with extraordinary activity, 
to microscopic organisms, to atmospheric dust, to the examination of material brought up 
from deep soundings, and to all questions appertaining to the sea. We must touch on one 
salient point, viz. , the connection he established between certain classes of living micro- 
scopic organisms, and the part they played in geological times. As early as 1836 he 
showed that the siliceous strata, known as “ Tripoli,” found in various parts of the globe, 
especially at Bilin in Bohemia, were but an accumulation of the skeletons of Diatoms, 
Sponges, and Radiolaria ; he pointed out that similar strata were formed now-a-days by 
Diatoms in the subsoil of Berlin. In 1839 his observations at Cuxhaven revealed the 
presence of living Diatoms and Radiolarians on the surface of the Baltic, of the same 
species as those found fossil in the Tertiary deposits of Sicily and Oran. He showed, 
moreover, that in the Diatom layers of Bilin the siliceous deposit had, under the influence 
of infiltrated water, been transformed into compact opaline masses. Starting from these 
facts, he concluded that rocks similar to those which play so important a part in the 
terrestrial crust are still being formed on the bottom of the sea. 
Humboldt addressed a letter to Lord Minto, First Lord of the Admiralty, with 
reference to Sir J. C. Ross’s Antarctic Expedition, calling attention to the importance of 
studying the microscopic organisms, which Ehrenberg had shown played so important a 
role in the constitution of terrestrial strata. Dr. Joseph Hooker, who was attached as 
naturalist to the expedition, observed ^ that the waters and ice of the Antarctic regions 
swarm with Diatoms to such an extent that they give the water a brown tint. Between 
lat. 50° and 70° S. prodigious quantities of them were found, and in 80° S. lat. all the 
surface ice, the sides of the icebergs, and the base of the great Victoria Barrier within the 
limit of the waves, were coloured brown by these organisms. He remarks that the siliceous 
^ Testaceographia et zoophytographia parva et microscopica, with 179 plates. 
2 Brit. Ass. Eepoit for 1847. 
(DEEP-SEA DEPOSITS CHALL. EXP. 1891.) 
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