Introduction to Life of the Lakes. 109 



and through them into its sediments the re- 

 mains of forest and field, burying them up 

 safely in its profoundest depth and thus 

 securing them from decay. The perfection of 

 this mode of preservation is well nigh com- 

 plete. The minutest vein work of the leaf; 

 the insect that fastened to its surface; the seed 

 pod or capsule of the plant; the pores of the 

 wood; the sutures of the animal's skull; the 

 epiphyses of the bones, enabling one to tell at 

 a glance whether these belong to the young or 

 the old; the minutest lines of age or accident 

 on a tooth; all are preserved with marvelous 

 faithfulness to the life type of the period, so 

 that no family of plants or of animals is likely 

 to have lived on the borders of the lake during 

 that long stretch of time, covering hundreds 

 of thousands of years, without sharing in the 

 record of its fossil history. It is from such 

 archives that materials have been collected 

 for a geological record of Oregon's past. 



In describing in such rapid succession the 

 changed condition of this region and of the 

 mountain barrier that walled it in on the west, 



