GEOLOGY. 71 



mantic sites, destined to become places of fashionable resort 

 when our pojnilation grows dense. There are so many of 

 these springs in the state that there is not room here to men- 

 tion them all. 



In San Bernardino valley there are a number of warm 

 springs. Their temperatures are thus reported: 108°, 128°, 

 130°, 166°, 169°, and 172°. The heat of the springs at Aguas 

 Cahentes, in San Diego county, is thus given: 58°, 74°, 130°, 

 136°, and 140°. 



Near Warner's ranch, in San Diego, is a spring with a tem- 

 perature of 135°, rising from a cleft in the granite rock. 



§ 51. Cortes Shoal. — About one hundred miles west of San 

 Diego is Cortes Shoal, twenty miles long and three miles 

 wide, with a depth of only fifteen feet in one place. This 

 shoal is evidently the summit of a submarine ridge of moun- 

 tains, parallel with the other ridges of tlie coast. The shoal 

 was discovered in December, 1852, by Captain Cropper, of the 

 steamship Cortes, who asserted that there was evidently a sub- 

 marine volcano in operation there. The water was in violent 

 commotion, and at intervals was thrown up into the air in col- 

 umns ; there was an escape of steam, and he suddenly found 

 the depth of water change from forty-five to nine fathoms. 

 He saw also light and smoke, and at one time the place looked 

 as though it were a ship on fire. The general opinion is, that 

 he saw only the Avaves breaking upon the Bishop Rocks, as the 

 rocks at the shallowest place are called ; but some persons ad- 

 here to his opinion of a submarine volcano. 



XoTE. — The chief writers upon the Geology of CaHfornia are W. P. Blake, 

 J. S. Newberry, an l Jules Marcou, in the United States Pacific Railroad Sur- 

 vey reports, and Dr. J. B. Trask's reports to the state legislature, and Jules 

 Marcou's book on the Geoloary of North America, For the chemical fineness 

 of the gold in the various mining districts, I am indebted to Henry Van Yalk- 

 eaburg. 



