TRUE VOLCANOES. 417 



(see above, p. 61, note 71) distinguished by a star. The high 

 conical mountains not so distinguished, are probably partly 

 extinct volcanoes, and partly unopened trachytic domes. 



Mount Pitt, or M'Laughlin ; lat. 4& 30', a little to the 

 west of Lake Tlamat ; height 9548 feet. 



Mount Jefferson, or Vancouver (lat. 44 35'), a conical 

 mountain. 



Mount Hood (lat. 45 10'), decidedly an extinct volcano, 

 covered with cellular lava. According to Dana this moun- 

 tain, as well as Mount St. Helen's, which lies more 

 northerly in the volcano range, is between 15.000 and 

 16,000 feet high, though somewhat lower 25 than the latter. 

 Mount Hood was ascended in August, 1853, by Lake, Tra- 

 vaillot, and Heller. 



Mount Swalahos, or Saddle Hill, S.S.E. of Astoria 38 , 

 with a fallen in, extinct crater. 



Mount St. Helen's,* north of the Columbia river 

 (lat. 46 12'). According to Dana, not less than 15,000 

 feet high 27 . Still burning and always smoking from the 

 summit-crater. A volcano of very beautiful, regular, co- 

 nical form and covered with perpetual snow. There was a 

 great eruption on the 23rd November, 1842 ; which, ac- 

 cording to Fremont, covered everything-to a great distance 

 round with ashes and pumice. 



Mount Adams (lat. 46 18'), almost exactly east of the 

 volcano of St. Helen's, more than 112 geographical miles 

 distant from the coast, if it be true that the last-named 

 and still active mountain, is only 76 of those miles inland. 



25 Dana (pp. 615 and 640) estimated the rolcano of St. Helen's at 

 16,000 feet, and Mount Hood of course under that height, while 

 according to others Mount Hood is said to attain the great height of 

 18,316 feet, which is 2521 feet higher than the summit of Mont Blanc, 

 and 4730 feet higher than Fremont's Peak in the Rocky Mountains. 

 According to this estimate, (Langrebe, Naturgesckichte der Vulkane, 

 Bd. i, s. 497), Mount Hood would be only 571 feet- lower than the 

 volcano Cotopaxi ; on the other hand Mount Hood, according to 

 Dana, exceeds the highest summit of the Rocky Mountains by 2586 

 feet at the utmost. I am always desirous of drawing attention to 

 variantes lectiones such as these. 



36 Dana, Geol. o) the U.S. Expl. Exped., pp. 640 and 643645. 



* Variously estimated previously at 10,178 feet by Wilkes, and 13,535 

 leet by Simpson. 



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