CHAPTER VII. 

 INTRODUCTION TO LIFE OF THE LAKES. 



In our narrative of the changes that oc- 

 curred in the Siskiyou region, the record we 

 tried to translate was made by the waters of 

 the ocean; in carrying out a like inquiry for 

 the Shoshone region, we have found ourselves 

 shut in to the record of its lakes. 



The ocean beach has no break in its rec- 

 ord, for the ocean always has a beach, and 

 the beach always makes its record, whether 

 kept or lost in later changes. The muddy sed- 

 iment of the lake lasts with the lake but ceases 

 to write when the lake dries up or drains off 

 and its record closes. The lake, then, keeps 

 the geological record of the interior of the 

 continent only while the lake lasts, the ocean 

 beach that of its external margin, and is con- 

 tinuous. It will be remembered when the 

 great sea dyke that formed the foundation of 



