256 J. Murray on Sea-bottom Deposits, 
nodules or concretions, of incrustations or in grains, has been 
found in nearly all sea-deposits and at all depths in more or less 
abundance. However, for the present it has been considered best 
to treat of its occurrence separately, at the same time pointing 
out those regions where we have found it in greatest abundance, 
few remarks may now be made upon each of the kinds of 
deposits indicated. 
1. Shore-deposits.—It has been found that the deposits taking 
place near continents and islands have received their chief char- 
acteristic from the presence of the débris of adjacent lands. In 
some cases these deposits extend more than 150 miles from the 
coast. Several varieties can be recognized among these shore- 
deposits. 
(a) Blue and Green Muds.—In the great majority of cases the 
deposits near continents and large islands, containing the older 
and crystalline rocks, have been of a blue or green color; the 
only exception appears to be the east coast of South America, 
where we have a red mud, to be presently referred to. 
In from 100 to 700 fathoms these deposits are often of a 
green color, due to the presence of a green amorphous clayey 
matter, and dark and pale green glauconite particles. Beyond 
700 fathoms they are usually of a blue or dark slate-color, hay- 
ing a thin upper layer of a red or brown. This red layer isa 
soit ooze, whilst the blue mud or clay beneath is very compact 
and tenacious. Much amorphous clayey matter and fine part 
cles of mica, quartz, and other minerals are found in all por 
pa, the mineral particles increasing in size as we approa¢ 
and. 
abundant, and that there were many of the shore aor ia 
Foraminifera, as Textularias, Rotularias, Nodosarias, Uvig 
arrier were muds of a blue color, containing many many 
and other pebbles and bloc stly rounded, an pee 
off the east coast of North America, Halifax to New ae 
Beyond 1500 or 1700 fathoms, Pteropod and H hardly a 
shells are usually not found, and in 3000 fathoms ee, 
Foraminiferous or other carbonate-of-lime organism remar 
