356 



University of California. 



[Vol. 1. 



For the strata composing the terrane from which this strange 

 topography has been evolved, it is proposed to use the name "Wild- 

 cat Series." The areal distribution of the terrane and the lines of 

 its demarkation from adjoining terranes are easily recognizable in 

 the peculiarities of the sculpture. The extent of the terrane has 

 not, however, been determined; but in a general way it may be 

 said to occupy a large tract of Humboldt County to the north of 

 Bear River Ridge, and east of Humboldt Bay. It is, doubtless, 

 also, extensively developed in the coastal region northward of 

 Eureka, and is known from fossils in the museum of the Univer- 

 sity of California, to be probably represented at Crescent City and 

 Coos Bay. 



The Femdale Section. — This Wild-cat Series is exposed in a mag- 

 nificently clear and unequivocal section on the ridge followed by the 

 stage road in descending from the Bear River Ridge to Ferndale, 

 on the southern edge of the Eel River flood-plain. The base of the 

 series rests unconformably on a basement of Mesozoic sandstones 

 at a point on the south side of Bear River Ridge about four and 

 one-half miles south of Ferndale, the beds dipping northward at an 

 an-de of about 15 . The contact on the road is probably about 

 1,500 feet to 1,600 feet above sea level. From this point the road 

 crosses the edges of the strata in a continuously ascending sequence 

 to Ferndale, where the highest beds pass beneath the plain. The 

 dip throughout this section is constantly northward (a little east of 

 north) at angles varying from 15 to 25 °. An enormous thickness 

 of strata is thus exposed. Taking 15 , the lower limit of the 

 angle of dip, a simple calculation gives 4,600 feet as a minimum 

 value for the thickness of the series in this section. As the upper 

 beds of the series, which have been truncated by the Eel River 

 flood-plain, are not included in this estimate, and as the dip fre- 

 quently exceeds 15 , the value for the thickness may safely be 

 placed at over one mile. 



Petrographically the strata consists of evenly-bedded yellow 

 and brown clays, which on desiccation, weather spheroidally, silty 

 clay shales, sandy clays, argillaceous sands, compact, but not firmly 

 cemented, common yellow sandstones very feebly coherent, and 

 pebbly conglomerates more or less firmly cemented. The clays are 



