SOUTHERN CALIFORNIA. 89 



in this region and tlie gold district to the north, have supposed that an equally diligent search 

 here would yield a like reward to the explorer. 



Nothing, however, has yet been brought to light to substantiate this view. The washing of 

 the different stream beds only shows the existence of iron in the form of black sand, and no 

 traces, or very indifferent ones, of the precious metals. This absence of metals we should 

 naturally expect where the crystaline rocks prevail. It is on the eastern slope of the mountains, 

 where talcose slate makes its appearance, with accompanying quartz veins, that we have most 

 reason to expect a correspondence with the gold district of the north. Still no discoveries have 

 as yet, pointed to any valuable result ; the quartz veins examined exhibit a very uniform thick- 

 ness of about 12 inches, and maintain a direction nearly north and south, without showing any 

 disposition to form branches ; all of which circumstances must be considered as unfavorable to 

 mineral productions. 



It must be left to future exploration to determine the true value to be given to the mineral 

 indications of this district. 



The often reported rumors of rich copper deposits in the vicinity of San Diego I have not been 

 able to trace satisfactorily to but one certain source. This locality occurs at some distance 

 south of the boundary line, near the Rancho Guadalupe. The spot itself I have never visited ; 

 but authentic specimens shown me exhibit a moderately rich copper ore^ composed mainly of 

 green malachite. 



Such a class of minerals we may reasonably expect to find in connexion with the extensive 

 range of greenstone porphyry adjoining the coast. 



There is no satisfactory evidence of the existence of silver ore, or of quick-silver, in the 

 district under examination. 



2. The entire absence in this region of any of the forms of stratified rocks comprised in the 

 older paleozoic or secondary period, serves to limit still further the prospective mineral wealth 

 of this district. It excludes at once the idea, which has frequently been in vogue, of the 

 existence of coal belonging to the carboniferous period. All the rumored reports of its discovery 

 which I have been able to trace are referrible to certain forms of tourmaline, or more commonly 

 to the existence of lignite or mineral asplialtum, so generally associated with the tertiary strata. 



3. The mineral products pertaining to the tertiary formation worthy of special notice are 

 but few. On the Pacific coast we have to include the various forms of mineral bitumen, a form 

 of Tertiary chalk, together witli various other alkaline earths. 



The mineral bitumen is quite extensively scattered over a large portion of the Tertiary district. 

 It occurs in most abundance where this formation acquires its broadest and thickest dimensions, 

 and is connected more or less with igneous disturbance. In the neighborhood of Los Angeles 

 it occurs in the form of what are popularly termed " pitch springs." In such localities, it is 

 observed issuing in the form of a tarry liquid, becoming hard and of a deeper color by exposure 

 to the air. In this latter form it resembles closely the pitch of commerce, and is applicable to 

 similar uses. In the vicinity of San Diego it is found in the form of irregular patches, spattered 

 over the sand rock, washed by high tide. It is also frequently met with in an erratic form, 

 being silted up by the waves at various points along the ocean beach. 



The more abundant product of the bitumen springs, in the vicinity of Los Angeles, is 

 principally in use for the sheathing of roofs, as a protection from rain. In the rough state in 

 12 M 



