47 



coast ranges, and of these Mount Shasta forms probably the line of eastern limit ; 

 its distance from the sea is a due west line not exceeding seventy miles, being a 

 much shorter distance from the ocean than many parts of the same chain situated 

 farther to the south. 



The mountain districts of this part of the State are divided by bold and rapid 

 streams, and as a consequence, are designated by local names which serve to fix 

 their geographical and relative positions, forming the boundaries of counties and 

 the lines of water-shed, which unite with the ocean at widely different and distant 

 localities. Thus we find the waters which flow into the Sacramento separated from 

 those which flow into the Klamath by the range known as the Trinity Mountains, 

 the latter river draining a portion of the waters belonging to the Great Basin, and 

 which rises east of the Cascade range. 



The rocks which comprise this part of the coast mountains are made up mostly 

 of the primitive group, and simulate in almost every particular with those found in 

 the mining counties of the Sierra Nevada, and also the southern portions of the 

 coast chain. In the eastern and middle districts of this part of the mountains, the 

 sienites and other members of the granitic series are largely predominant, and com 

 mingled irregularly with them, are found the serpentine rocks and their derivatives, 

 consisting of the talcose and chlorite schists, alternating with all the other members 

 of the primitive group. 



Resting upon these we find the slates of an argillaceous origin frequently disturbed 

 and maintaining every conceivable degree of inclination, as in the other mining 

 counties of the State, but still holding their parallel with the mountains in which 

 they are situated, which is observable elsewhere, and the same line of strike or 

 linear direction. The constancy and regularity of the strike found in these rocks 

 at such remote distances from those of the southern range of mining counties leads 

 us irresistibly to the conclusion that they belong to one and the same period and 

 co-relative age, having their origin from the same class of rocks as those of the other 

 sections. The subsequent igneous intrusions which have disturbed the one are 

 found to be of the same character as those which disturbed the other, and have 

 apparently acted with the same force and at the same time with those of the Sierra 

 Nevada. The intrusions of quartz dikes and veins appear equally as numerous 

 and well defined as those found in any other part of the State, and even much 

 more extensive than many of those observable in the midland counties. They simu 

 late more closely with those veins found in the counties of Tuolumne, Calaveras 

 and Mariposa. 



In the depressions lying between the principal divides of the various rivers, the 

 heavy drift deposits are met with ; in some localities they extend to great depth, as in 

 the vicinity of the town of Weaverville, they have been found to the depth of nearly 

 five hundred feet, which was proved by the sinking of the deep shaft near that town. 

 This drift, or the greater part of it at least, has all the evidences of having been 

 deposited during the tertiary epoch, the manifestations of which are found in the 

 great amount of the impressions of dicotyledonous leaves, many of which are appa 

 rently of present existing species found growing in the neighboring mountains ; the 

 silicified woods and lignites all present thesame general features. 



This district is peculiarly interesting from the great amount of drift deposits 

 which are present in many localities, and the character of the organic remains con 

 tained in it is well defined, and will probably be the means of modifying our opin 

 ions in some measure, relative to the probable age of the drift deposits of the 

 different portions of this State. There are apparent grounds existing, (which, how 

 ever cannot be fully demonstrated at the present time) that these drift beds are 

 assigned to two distinct periods of the tertiary era, but more time and further exam- 

 nation must be had before this point can be satisfactorily settled. In an economical 

 point of view it matters but little to which of the two periods, either of them may 



