The Pegmatyte Veins ofPala — Waring. 357 
«of -intrusive dioryte dykes and later granite intrusions 
within the main granite mass. These dykes in the western 
part of the area in question have a rather constant N. E.^- 
.S. W. strike. They are of considerable extent, the one em- 
bracing Red mountain, near Fallbrook, being fully a mile 
wide, while the smallest one traced was about two hundred 
yards wide. 
Toward Pala the general strike of the dykes swings to 
the N. W.-S. E. The contact lines are usually well marked 
by a change in the character of soil and vegetation, and by 
intrusive lenses of the dioryte in the granite at the contact. 
The normal dioryte is composed of green hornblende and 
plagioclase, in a few places also carrying hypersthene. At 
Pala the rock is more basic, becoming a hypersthene gabbro 
or noryte. Smaller dykes occur in the granite, but these 
are of a granulitic structure. Three types have been ob- 
served : green hornblende granulyte, garnet granulyte, and 
biotite granulyte. ,•■•-,■. 
The granite also varies in texture. Two kinds occur, 
•one locally called "blue granite," in which the hornblende 
is altering to chlorite and the oligoclase sh,ows marked 
zonal structure ; and a lighter variety, containing little horn- 
blende. West of Fallbrook the darker variety appears As 
intrusive more resisting areas in the lighter. To the east 
the Vallecitos valley is a region of light colored granite, 
varying from a rock almost without hornblende to areas 
•containing large patches of this mineral. The origin of the 
valley is thought to be due to the differential weathering of 
this granite. Veins of feldspar cut the granite in all 
•directions. 
The varying texture of the country rock is well shown 
by the section as described by Fairbanks,* exposed in 
Temecula canyon. "A wholly different series of rocks is 
exposed in Temecula canyon not more than two miles north 
of the country just described, [Vallecitos]. This canyon 
is deep and rocky, taking a' very direct course from Teme- 
cula to the ocean. At the upper entrance there is a nar- 
row exposure of granite. This is followed by quartzyte 
* Eleventh Annual Report of California State Mineralogist, p. 101. 
