GEOLOGY OF BAJA CALIFORNIA. 185 



It is seen at once that the section is in some respects 

 quite similar to Blake's above mentioned profile north of 

 the boundary line, and that it is almost exclusively made 

 up of granite and metamorphic slates, the former much 

 predominating. 



THE FIKST GEOGRAPHIC BLOCK OR THE COAST RANGE. 



Leaving the small quaternary valley of Ensenada, the sec- 

 tion runs, gently ascending, on the divide between Ensena- 

 da and Gallo Creek; to the right and left rugged masses of 

 porphyrites rise above the granite floor. At a distance of 

 ten miles from EnseDada the road descends in the Gallo 

 Creek and continues along it up to the first divide. The 

 granite is a hornblende granitite of coarse grain and white 

 color, weathering into rounded blocks, and finally giving a 

 sandy, barren soil. It is in composition and texture 

 equivalent to the granite of the Sierra Nevada. The char- 

 acter appears to remain very constant. 



Twelve miles from Ensenada, in the Gallo Canon, meta- 

 morphic rocks are met with, extending for five miles, up to 

 within two miles of the first divide. 



In passing the contact, one gains the decided impression 

 that the metamorphic overlies the granite; the former con- 

 tinues up on the hills above the caiion, while the bottom is 

 yet in granite. 



This metamorphic series is at first glance not easy to 

 recognize as such. Passing through the canon rapidly one 

 would be tempted to refer it to massive rocks. The first 

 few miles run over chloritic and micaceous slates, mixed 

 with other very indistinctly stratified metamorphic rocks. 

 The chloritic schist runs N.W.-S.E. to N.-S. and stands 

 nearly vertical. Farther on the stratification ceases 

 entirely, and brown, irregular outcrops of dense to 

 middle - grained dark -green dioritic and diabasic rocks 

 prevail. Approaching the eastern edge of the area 

 this habit becomes more apparent, and the rocks ad- 



