.172 AN AMERICAN GEOLOGICAL RAILWAY GUIDE. (CAL. & W. T.) 



38. The only groves of the celebrated " Eedwood " tree, accessible by railroad, are on this 

 route and northward. J- & C. 



Washington Territory. 1 



1. Furnished by Prof. Condon, the State Geologist of Oregon. 



2. Basalt is an igneous rock occurring in the volcanic and trap series. The 18. Cretaceous era, 

 and still more the 19. Tertiary and 20. Quaternary, were remarkable for the extent of ^he eruptions 

 over the western part of this continent in Oregon, Washington, &c. Basalt being an intrusive rock 

 is not here distinguished by any number denoting its age, as that can only be.known by the forma 

 tion on which it rests, or that resting upon it, if there be any. 



