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THE DEPTH AND MARINE DEPOSITS OF THE PACIFIC OCEAN. 23 
tively 40, 65, 58, 72, and 65 per cent of calcium carbonate, and also in one 
sample containing 33 per cent of calcium carbonate, which might be called 
a Red Clay. The samples were dredged in stations situated as follows : — 
Latitude. Longitude. Depth. 
Le aS ioe 100° 52’ W. 2168 fathoms. 
21° 36'S. 181° 35’ W. 2228 + 
aL. LVS. Lebo, 21 We 2128 * 
BOs OL Ss 126° 53’ W. 2042 =& 
We ATs 123° 20’ W. Sono 
21°-39' 8. 104° 29’ W. 2422 = 
These deposits have a truly pelagic character, having been formed far from: 
land, so that the mineral elements contained in them have mostly a volcanic 
origin. 
Reference to the descriptions will show the widespread distribution 
of such minerals as volcanic glass, palagonite, pumice, etc., while augite and 
felspars have almost certainly the same origin. 
From the foregoing facts it will be seen that when a Globigerina Ooze 
forms far from land, its nature, when calcareous organisms are not taken 
into account, is very similar to that of a Red Clay, not only as regards its 
chemical composition, but also as regards secondary products formed in situ. 
It may be added that the minute calcareous coccoliihs and rhabdoliths are 
nearly always represented, but never in large amount, so that they have 
not been indicated in the descriptions. 
In Red Clay the minerals had to be put down as “traces” in the great 
majority of the descriptions; the highest percentage observed is one of 4 
per cent at Station 4658, and even then the 4 per cent is nearly wholly 
represented by manganese grains. Actual mineral particles, volcanic or 
continental, never make up an appreciable amount as such, but, of course, 
if one could devise a means of separating and estimating the very minute 
particles that pass away in decantation together with the “fine washings,” 
the relative percentages would be widely different. In the present study 
the mineral particles together with the siliceous organisms were always dried 
and weighed, and the relative proportions of siliceous organisms and minerals 
roughly estimated by counting the particles spread on a microscopic slide. 
When the weight of the residue was so small as to fall within the limits of 
experimental errors, minerals and siliceous organisms had to be estimated as 
traces. 
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