24 [APPENDIX 



Umhumin,) the latter being the original Indian name applied to this 

 hill. 



The entire range is composed, principally of the primitive rocks, among 

 which the serpentine formations play an important part ; this suite was 

 traced from near the Rancho La Brae on both flanks of the mountains, 

 to the Francisquito on the east side, and Anno Nuevo on the west, and 

 belong to ths same series as those occuring at Point Lobos and the Pre 

 sidio. In several instances throughout the range, the trapean rocks have 

 broken through, as detailed of the mountains south of Monterey. 



On the west flank of these mountains, and in the central and northern 

 parts of the .County of Santa Cruz, there are views of quartz cutting 

 through the serpentine and other rocks in other places ; and is particu 

 larly observable on the upper portions of the arroyas Sogell, Syant, and 

 Bio San Augustine. The general rule heretofore laid down respecting 

 the contact of these two groups of rocks in this country is found good 

 in the present case. " That when the two series are found in contact, 

 either as dikes of great length, or smaller views, one, or both is always 

 auriferous." And such has proved to be the fact in the case before us ; 

 from all appearances the quartz has been one of the most recent disturb 

 ing agents here, as well as elsewhere. 



The mineral characteristics of these mountains will be noticed more in 

 detail when speaking of that subject hereafter. 



The south-east spur of these mountains terminates at the Pajaro River, 

 thirty-six miles east of Santa Cruz, and fourteen from Watson ville. On 

 the southern extremity are found - extensive beds of fossils finely pre 

 served. The arroyo Peseadero and la Brae cut their way through these 

 hills, and their beds abound with boulders containing these organic re 

 mains. The fossil sandstone at this point rests on the Serpentine and 

 trapean intrusions, being changed in its texture near the" points of contact 

 with the latter rocks. . On these streams are to be found several bitumi 

 nous springs, which discharge large quantities of the fluid bitumen, at 

 times covering several acres of ground. The occurrence of these springs 

 has led to the belief that bituminous coal existed in this section, such, I 

 think, is not the fact in the present case, though it might be a tenable sup 

 position in parts of the world where coal measures exist, or where any of 

 the superior groups of the secondary rocks may be found. 



The position of these springs, geologically considered, would render it 

 impossible for coal to abound, as -they make their appearance among a 

 mass of rocks having an igneous origin, where not even a lignite is likely 

 tp exist. There is but a possibility that the tertiary rocks in the vicinity 

 may overlie some members of the secondary group, from which these 

 springs have their origin, but no outcrop or other indications are to be 

 found which will warrant such a conclusion. There is every evidence 

 that the tertiaries above rest on the primitive and volcanic rocks with no 

 intermediate series between them. The origin of bituminous springs is 

 but little understood ; in the present state of our knowledge they are 

 found to arise from the newer as well as the older formations, and alone 

 are not reliable evidences of the existence of coal, except when found 

 among. the carbouiferou-s rocks. 



Following the east flank of the Santa Cruz mountains, we find small 

 patches of the tertiary sandstones among the lower portions' of the hills, 



