60 THE MOUNTAINEER 



rocks were brought into the Olympics and deposited there by great glaciers 

 which at one time came down Irom the Cascades an. I from the mountains of 

 l^ritish Columbia. The glaciers occupied the Puget Sound basin and filled 

 the broader valley of the 01ym])ics. 



In the history of the earth we tlnd nuiny i)rinci])les which govern the 

 study of human history. A study of the rocks and their fossil contents 

 gives us a history of the geological development of our planet in the same 

 way that a study of records, archives and works of art of former nations 

 and races gives us a history of human civilization. In human history we 

 have periods such as ancient, medieval and modern, and their subdivisions, 

 so have we in geology; the only difference being that in geology we regard 

 time as much longer than in human history. We conceive of geological 

 periods in millions of years rather than in hundreds, the major divisions 

 of geological time ranging from the older to the younger are si)oken of as 

 the Archaean, Palaeozoic, Mesozoic, Tertiary and Recent. Within the 

 Olympic peninsula, the Archaean and i)roba])ly the Palaeozoic rocks are not 

 represented. 



The hard metanu)r])hic rocks comi)osing the great central portion of 

 the Olympic mountains in all probability belong to INIesozoie time. These 

 rocks are made up for the most part of quartzites and schists, which at one 

 time before they were metamorphosed were sandstones, conglomerates and 

 shales. They have been uplifted into a mountain mass and then folded and 

 cram])led and possibly invaded by great masses of igneous rock from deep 

 down in the earth's crust, but which have never penetrated the surface. 

 The result has been that these intense crustal movements have folde I and 

 disturbed the strata so that they no longer lie horizontal, but are tilted up 

 on edge. Such disturbances have caused cracks and fissures to be formed, 

 both large and small, and in these we have deposits of silica, well known 

 as quartz veins. Sandstones, which originally contained pebbles and large 

 l)Oulders, have been squeezed to such a degree by the folding processes 

 that the pebbles which were originally round and nearly spherical have 

 been drawn out into great long elliptical forms, sometimes ten or fifteen 

 times as long as they are wide. The majority of them are all elongated 

 in the same direction «,nd parallel with the strike or general direction in 

 which the layers of the strata extend. A section across the strike of the 

 strata, which in other words represents the character of the materials com- 

 posing the beds from base to top. is beautifully represented in following 

 up the Elwha river to its headwaters. The Tertiary lavas and sandstones 

 which have been mentioned extend from Port Angeles to a point about four 

 miles above McDonald, on the Elwha. Beyond this the slates and schists 

 are represented. North of this contact the metamorphie rocks probably 

 underlie the Tertiary formation. Between McDonald and Geyser the 

 metamorphie rocks appear to be made up largely of slates with only a small 

 proportion of ([uartzites and schists. The schist is simply a shab^ which 

 has undergone much more intense metamorjihism than the slates. As one 

 l^roceeds further along the strike and examines the area along the Elwha 

 between Gelser and Elkhorn, he finds the effects of metamcr :)hism to be much 

 more pronounced, schist and quartzite becoming much more common. The 

 fra'^turing of the strata is more noticeable and every now and then a quart'^ 

 vein may be observed. Farther up the valley near the Godstein, and even 

 u{) to the Elwha basin itself, the effects of metamorphism become much nu^re 

 marked. In the vicinity of the basin b-'d rock is finely exposed. The recent 



