26 The Two Islands. 



A minute and careful study of such rocky 

 forms by some of the best minds of the pres- 

 ent century, has secured such results that stu- 

 dents of geology may now speak with confi- 

 dence of many great changes in the former 

 life of the world. So carefully have the re- 

 sults of these geological studies been formu- 

 lated that it is entirely practicable to tell what 

 portions of any country were first above the 

 seas, and often to trace the successive addi- 

 tions to the land until its outline is recog- 

 nized as the present continent. 



Following this method in deciphering the 

 geological history of Oregon, one is carried 

 back to a time when this region, which we 

 now call our home, was covered by the ocean. 



In the natural world the evident results 

 of violent upthrusts of portions of the earth 

 crust are now accepted as among the trust- 

 worthy records of many lands. These dis- 

 turbances were sometimes accompanied by 

 great heat, often by violent earthquakes and 

 the outflow of melted rock, and sometimes 

 only by heat enough to change the materials 



