ON ITS EXTERIOR. TOLCANOES. 399 



Several littoral or coast chains run parallel to the 

 chain of the Rocky Mountains, sometimes in single, 

 sometimes in double ranges ; and in their northern por- 

 tions (from 46 12' N.) are still the seat of volcanic 

 activity. We have first, from San Diego to Monterey 

 (from 32ito 36jN.), the "Coast Range," specially so 

 called, a continuation of the ridge of land of the penin- 

 sula of Old or Lower California ; then, generally at a 

 distance of about 80 geographical miles from the shore 

 of the Pacific, the Sierra Nevada (de Alta California), 

 from 36 to 40 J; then, beginning from the high 

 Shasty Mountains in the parallel of Trinidad Bay 

 (41 10'), the Cascade Range, which includes the highest- 

 summits still burning, and extends from south to north, 

 at a distance of 104 miles from the coast, to far beyond 

 the parallel of the Fuca Strait. Running in the same 

 direction, from 43 to 46 N., but at a distance of 280 

 miles from the coast, the Blue Mountains rise to a mean 

 height of 8000 feet. ( 548 ) In the middle portion of Old 

 California, but a little to the north, near the eastern 

 coast (the western shore of the gulf), in the district of 

 the former mission de San Ignacio, in about 28 N., we 

 find the extinct volcano, called the "Volcanes de las 

 Virgenes," which I have set down in my map of Mexico. 

 This volcano had its latest eruption in 1746 : we require 

 more certain information respecting both it and the 

 whole surrounding district. (See Venegas, Noticia de 

 la California, 1757, t. i. p. 27 ; and Duflot de Mofras, 

 Exploration de 1'Oregon et de la Californie, 1844, t. i. 

 pp. 218 and 239.) 



Rocks belonging to ancient volcanoes have been already 

 found in the Coast Range near the port of San Francisco, 



