38 BULLETIN OF THE 
The mineral particles consist of fragments of ancient rocks, quartz, 
monoclinic and triclinic felspars, magnetite, hornblende, augite, mica, 
tourmaline, and occasionally glauconitic grains. 
In 1240 fathoms, and Lat. 38° 34! N. off this coast, the “ Challenger” 
dredged many rounded and angular pebbles of milky and hyaline quartz, 
fine-grained quartzites, felspathic quartzites, mica schists, serpentine 
rocks, and compact limestones. These fragments were not larger than 
6 or 7 centimetres in diameter. The “ Blake,” in 1241 fathoms and 
Lat. 39° 43’ N., dredged similar, but much larger, fragments of the same 
rocks, some of which were glaciated. In Lat. 41° 14’ N. and in a 
depth of 1340 fathoms, the ‘‘ Challenger” again dredged similar rock 
fragments, and one block of syenite weighing 5 cwt. These deposits 
being all within the influence of the Labrador Current, these rocks may 
be regarded as chiefly ice-borne. 
The carbonate of lime in these deposits consists of coccoliths and 
coccospheres, of pelagic and other Foraminifera, and of fragments of 
Echinoderms, Polyzoa, Ostracodes, and Mollusks. The pelagic Forami- 
nifera shells and coccospheres are more abundant in the deeper deposits 
far from the land than in those from shallower water near the coast. 
The siliceous remains of Diatoms, Radiolarians, and Sponges, together 
with arenaceous Foraminifera, and glauconitic casts of calcareous Foram- 
inifera make up sometimes 4 or 5 per cent of the deposit. 
The following are descriptions of some of the typical deposits :?— 
Station 305. — Lat. 41° 13’ 53” N. Long. 65° 57’ 25” W. Depth, 810 fath- 
oms. Surf. temp. 563°. Bot. temp. 39°. Gray mud, brown when wet, earthy, 
plastic, dries into hard lumps. Mixed with the mud were some few pinnule of 
Crinoids, also a few rock fragments (sandstone, diorite, and diabase) measuring 
from 10 to 30 millimetres in diameter. 
Carbonate of Calcium, 5.08 per cent, consists of coocoliths and coccospheres, 
fragments of Echinoderms, and the following foraminifera : — 
1 The methods employed in the examination of these deposits are the same as those 
adopted by Messrs. Murray and Renard for the Challenger deposits. The carbonate 
of calcium was determined by estimating the carbonic acid, weak and cold hydro- 
chloric acid being used for the purpose. The part insoluble in the acid is designated 
‘‘residue,” which by washing, decantation, and microscopic inspection is separated 
into three parts : (a) Minerals, the contraction m. di. indicating their mean diameter 
in millimetres ; (6) Siliceous Organisms, including the glauconitic casts of forami- 
nifera and other calcareous organisms ; (c) Fine Washings, including those particles 
which, resting in suspension, pass with the first decantation. The numbers in 
brackets indicate the percentage of the whole deposit. 
