Geological Papers. 159 



Pacific shore-line. So far no rocks of this age have been found on 

 the north slope of the peninsula. 



In speaking of the rock structure Professor Gil man says:^*^ 



''The country rocks of the mountains are syenite, gneiss, quartz- 

 ite, protogene, crystalline and chlorite schists, slate (hard, black, 

 flinty, to soft, green, talc), shale, sandstone, trap and basalt." 



The series containing the syenite, gneiss, quartzite, protogene, 

 crystalline and chlorite-schists is here placed by the writer in the 

 supposed Cretaceous. Its approximate area is not known, neither 

 is its thickness where the central core of the western extension of 

 the Olympics is exposed. Along the east and west axisof the western 

 part of the peninsula at Beaver Falls, on the East Clallam-La Push 

 wagon-road, which is composed of a very hard, dark-gray plutonic 

 rock of more than 10.000 feet in thickness. This core, however, is 

 exposed only in patches. Its greatest thickness is in the vicinity of 

 Clallam Peak. Towards Cape Flattery it is capped with sedimentary 

 deposits. Here it is composed of metamorphosed sandstone and 

 quartzite. It may prove to be of Eocene age. 



At Portage Head, Point of the Arches, and at Point Granville 

 the type rock of this old series is conglomerate, quartzite, old dia- 

 base or greenstone, serpentine, etc. 



This old series, wherever found, is much fractured and faulted 

 and cut by quartz veins, which occasionally carry gold and silver 

 in small quantities. The principal veins carrying precious metals 

 are found in the Point of the Arches group and in the vicinity of 

 Clallam Peak and Beaver Falls. An odor of benzine is also given 

 off from the serpentine and conglomerate rocks of this group in the 

 Point of the Arches, derived likely from the shales that are found 

 a mile further south. There are no other shales or oil-producing 

 rocks in the vicinity; the age of these shales is in doubt, but they 

 are Cretaceous or still younger. 



As a closing remark on this formation, the observations seem to 

 show that the oldest rocks of the peninsula are those on the Pacific 

 coast mentioned above, together with those in the Clallam Peak 

 group (?). The Pacific coast groups were islands in a Cretaceous 

 sea, and around them were deposited the next formation described. 

 The western extension of the Olympic axis, including the Clallam 

 Peak group, was caused by an upthrust movement along this line 

 at or near the close of Miocene times. Where the mainland mass 

 was in pre-Cretaceous times cannot be even suggested at this time. 



S'f'pposf^d Cretaceous. — There are three groups of rocks which 



20. National Geographic Magazine, vol. 7. 1896, p. 138. 



