CHEMICAL COMPOSITION IN SEDIMENTS 465 
from a well on Settlement Hill, two miles northeast of Stonington. 
The rock of this hill is wholly granite and it is largely bare of drift. 
The hill which is 120 feet high forms a peninsula connected by a low 
narrow neck to the main part of Deer Isle. Being thus practically 
surrounded by the ocean waters, its groundwaters quite certainly 
derive their mineral content from the granite of the hill. The 
analysis of water from a well 279 feet deep in the granite here is as 
follows: 
Parts per Million 
MRO PALESOLG Siycy pease h ye suast seater dee stccsdoss sta smiteneTePatete thousguieva tie ac 136.0 
Orgamiciandtvolatilenma tenis c sc uc on shasta o ole nies ope what e els 19.0 
Silica (S © a) yee etre ee ote em ce ie ate ee A antl aS ae Cen Il.2 
Tron and aluminum .oxides (Fe.O0,-+Al.O;)............... 2.0 
Calcium (Cale Pewee es Rie oe or petee Centers rare wench he daresicls 5 29.0 
Maro esiniriia (Mig) emcees case act tciey ai leis oyeysle tier sheieisnanere eheks 3:4 
SOG UIT INA) Ware eer neta t aa te har bile. cee Na Ny 1 cial ala! i acter £350 
OLAS Shura Meer cies ta)s pars dase she tecancdel anal apsgataakel sialoneass E.9 
Sulphatemradrcall(SO pees e i eracpac rine Colas ccomie aie oats 26.0 
Ghilorime x (Sleeve ees ey oe este ein cat say clever ere iscane ana ed 17.0 
The granite of this hill shows dominant potash with orthoclase- 
microcline as its dominant feldspar. In the solution of its constituents 
by the groundwaters the alkali ratio has therefore been reversed. 
Contamination from sea water is very improbable, not only in the 
nature of the case, but because of the low chlorine content. The 
dominance of lime over magnesia in the water is also greater than in 
the granite, indicating that the lime is being removed more rapidly 
than the magnesia. 
Instances of a character similar to those cited above might be 
multiplied to show the general tendency for soda to be removed more 
rapidly than potash in the processes of rock weathering. While 
this is the general rule exceptions are of course numerous. 
There is no evidence of important changes in the potash-soda 
ratio in the pelitic sediments during dynamic metamorphism and the 
development of foliated structures. Jf we compare the percentages 
of potash and soda in the analysis of the composite sample of 78 
shalest made in the laboratory of the U. S. Geological Survey, with the 
t See F. W. Clarke, ‘‘The Data of Geochemistry,” Bull. 330, U. S. Geol. Survey, 
p. 468 (1908). 
