1906-7.] The Composition of Terrigenous Deposits. 
269 
XXVII. — The Composition of Terrigenous Deposits. By F. W. 
Clarke, D.Sc., LL.D., Chief Chemist, U.S. Geological Survey. 
Communicated by Sir John Murray, K.C.B., F.R.S., etc. 
(Read July 8, 1907. MS. received July 10, 1907.) 
For purposes of comparison with the analysis of a composite sample of 
Red Clay recently published in the Proceedings ,* I have received from 
Sir J ohn Murray a composite of fifty-two “ terrigenous ” clays, dredged up 
from oceanic depths ranging from 140 to 2120 fathoms. In the nomen- 
clature of the Challenger Expedition, forty-eight of the individual samples 
are classified as “ blue muds,” and four as “ green muds.” Twenty- three of 
the clays were collected by the Challenger ; the others were brought in 
from voyages of the Buccaneer , Dart, Egeria, and Rambler. The range of 
collection, as in the case of the “ red clay,” was world- wide, and all of the 
great oceans are represented in the composite sample. The results of 
analysis appear in the following table : — 
A. 
B. 
C. 
SiO„ .... 
46-64 
J 
5 j 
57-09 
Ti0 2 , .... 
1-04 
1-27 
XI2O3, .... 
Cr 2 0 3 , .... 
14-08 
•044 
l -14 • 
17 24 
•05 
Fe 2 0 3 , .... 
4-14 
5-07 
FeO, .... 
1-88 
2-30 
Mn0 2 , .... 
•10 
•12 
MgO, .... 
1 95 
•18 
2-17 
CaO, .... 
7-20 
•38 
2-04 
SrO, ..... 
025 
■03 
BaO, .... 
•05 
•06 
K 2 0, .... 
1-84 
2'25 
Na 9 0, .... 
2-98 
2-12 
1-05 
V 2 0 3 , . . . . 
■028 
•03 
P 2 0 5 , ... . . 
•17 
•21 
co 2 , 
4-05 
so 3 , 
•32 
•32 
s, 
•11 
13 
Cl, . . . . . 
2'25 
2-25 
CuO, .... 
•016 
•02 
C, 
1-38 
1-69 
H 2 0 at 105°, . 
4-73 
H 2 0 above 105°, 
5*86 
718 
Less O = Cl, 
100-883 
•56 
! 
100-00 
100-323 
* Proc. Roy. Soc. Edin ., vol. xxvii., pp. 167-171. 
