I.AWSON.J 



Coast of Northern California. 



257 



most abundant at the bottom of the series; the compact sands and 

 soft sandstones predominate towards the middle, and the gravel 

 beds become prominent features only in the upper portion. Thin 

 layers of marine shells in a fragmentary state are observed at vari- 

 ous horizons, but owing to their frail condition they are difficult to 

 collect. 



The section thus briefly described is clearly the limb of a 

 synclinal trough whose axis has a strike of a little south of east. 

 Strata dipping southerly, and thus corresponding to the northern 

 limb of the syncline, were observed to the north of Eel River, but 

 the country was not sufficiently explored to ascertain whether the 

 sequence was repeated. There seems to be, however, no reason to 

 doubt that the structure is that of a simple syncline, and that the 

 course of the Eel River near its mouth lies approximately in the 

 synclinal axis. 



Relation of Sculpture to Geology. — In examining this Ferndale 

 section it becomes apparent that, although the result of the sculpture 

 of the terrane is a seemingly chaotic assemblage of sharp peaks 

 and ridges, the process of sculpture itself follows a well-known simple 

 law. The erosion differs only in the intensity of its action from that 

 of any other region of tilted stratified rocks. This intensity is due 

 entirely to the excessive softness of the beds in general, and to the 

 frequent alternation of slightly harder and softer rocks. In this 

 particular belt of the Wild-cat Country the transverse drainage is 

 northward to the Eel River across the edges of the northerly dip- 

 ping beds. The terrane being of soft material, great numbers of 

 such streams have been inaugurated. On either side of these drain- 

 age lines very numerous lines of subsequent drainage have been 

 pushed laterally along the strike, the soft character of the strata 

 enabling most of these to persist till they have met the advance of 

 the corresponding canons from the opposite side of the ridge, or 

 have alone traversed the ridge. Qualitatively this is the normal 

 process of land sculpture in all tilted sedimentary terranes. It 

 differs, quantitatively, however, in the excessively large number of 

 drainage lines which have been established, thus effecting a much 

 more minute chopping up of the original block form. If, now, the 

 terrane were composed of strata which persistently offered marked 



