90 
THE VOYAGE OF H.M.S. CHALLENGER. 
Maury's Tables 
of Sounding.-* in 
mu I>BKr Sea. 
TeUM.KAFH 
Plateau of hie . 
Atlantic. 
Absence or 
Current- in 
Debt Water. 
Volcanic A.-hes. 
• 
white.” 1 He concludes that these glauconitic easts have not been transported from 
ancient formations, but have been formed where they were found in the same manner as 
ii gc -logical formations. He states that his own and Ehrenberg’s researches prove that 
-■tiler organisms, besides Foraminifera, may serve as moulds for the greensand, and he 
notices that with the well-defined casts are associated green grains less regular in form, 
“having merely a rounded, cracked, lobed, or even coprolitic appearance.” 2 The 
ph' nomena accompanying the decomposition of organic substances, he says, are closely 
: uected with the formation of this mineral — a green or red silicate of iron or almost 
pure silica. 
Maury gives tables of soundings obtained up to 1857, showing those of the “Albany” 
(1850-51), the “ Dolphin ” (1851-52, Captain Lee), “Dolphin” (1852-53, Lieutenant 
Berryman), “Jamestown” (1851), “Plymouth” (1851), “Janey” (1849), “Saratoga” 
C850), “ Congress ” (1851), “ John Adams” (1851), “Susquehanna” (1851), “St. Louis” 
<1852). and “Saranat (1853). He notes the rate of descent for each 100 fathoms, as 
observed in each of the principal expeditions, discussing the results of the soundings and 
making use of them in the construction of his bathymetrical map. 3 
In 1856 Lieutenant Berryman, in the steamer “Arctic,” sounded across the North 
Atlantic, the principal object being to verify the discovery of a long submarine ridge 
between Newfoundland and the British Islands, to which the name of Telegraph Plateau 
had been given, and along which a company was preparing to lay a cable. He obtained 
samples of the deposit from tliirty-four points between St. John’s, Newfoundland, and 
\ dentia. These deposits were described by Bailey, 4 who, from the fact that the mineral 
particle were angular, concluded that there is little movement at the bottom in deep 
water, otherwise the mineral fragments would be rounded. This confirmed what was 
already known as to the relative immobility of very deep water, and was of considerable 
mportance with reference to the cable about to be laid, as it showed the small chance of 
displacement through bottom currents. He observed the abundance of calcareous matter 
due to the accumulation of microscopic shells, which fall to the bottom after the death 
of the organisms. Bailey also observed the presence of volcanic ashes in the deposits, 
and remarked that the Gulf Stream had spread these “ plutonic tallies” over thousands 
of miles ; this most important discovery was to receive further confirmation and general- 
isation from the subsequent observations of Maury. Some doubt having arisen as to 
whether these ashes might not have been thrown overboard from passing steamers, 
Bailey compared the two, and arrived at the conclusion that the substances found on the 
bottom of the Atlantic were really of volcanic origin. Maury supposed that this dust 
. 1 1 . /lit have b cu carried by the wind from volcanoes in Central America or from extinct 
\ olcauoc in the Western I -lands, though admitting the difficulties in the way of account- 
1 I’roc. Baton Hoc. Xat. llut., vol. v. p. 367. 
* Maury, op. ril., pi. xi. 
1 Ibid., p. 368. 
4 Arner. Journ. .Set., aer. 2, vol. xxi. pp. 2S4-285, 1866. 
