xlviii PJiT/sical and Geognostic Suggestions, 



Colima, Tunguragua, Purace, Paramo de Ruiz, and the 

 Peak of Teneriffe, which has recently been accurately exa- 

 mmed by Mr. Charles Deville. The trachytes of Toluca, 

 Orizaba, Gunung- Barang, and Burung Agung, on the Island 

 of Java, Argseus, in Asia Minor, Cuneguilla, south of Sta. 

 Fe de Nuevo-Mexico, the Sierra de San Francisco, west of 

 the Rocky Mountains and Pueblo Zuni, consist of horn- 

 blende, oligoclase, and brown mica. The trachytes of 

 Stroraboli and Etna, those of the Siebengebirge (Drachenfels), 

 and of Kara Hissar in Phrygia, consist of large crystals of 

 glassy felspar, with numerous smaller crystals of oligoclase, 

 some hornblende and mica. Oligoclase, having been mistaken 

 for albite, led to the fantastic idea of a peculiar rock, the 

 Andesite, prevailing in the Andes, and even led our great 

 master, Leopold von Buch, to make some curious distinctions, 

 (Description des lies Canaries, 1836, pp. 186-87.) 



To ascertain the average height above the level of the 

 sea, I propose that furrows should be cut in the rocks of the 

 different regions along with inscriptions, which might carry 

 information to unborn ages, as has been done, on my sugges- 

 tion, now some 25 years ago, by the Academy of Science 

 at St. Petersburg, on the Caspian Sea, while Sir James Ross, 

 in his " Voyage of Discovery in the Southern and Antarctic 

 • Regions," 1839-43, Vol. II. p. 23, regrets not having done 

 so, or, at least, of having- only once adopted this plan. 



I would also, with all deference, suggest observations re- 

 garding the daily atmospheric variations or tides, so as to 



