400 COSMOS. 



came mountain-strata, and where friction produces what is 

 called ashes and fragmentary sub-division, give rise to small 

 and for the most part transitory cones of ejection, which are 

 not to be confounded with the great terminal cinder-cones of 

 the permanent structural frames. 



Close by the Society Islands, in an easterly direction, are 

 the Low Islands, or Paumotu. These are merely coral islands, 

 with the remarkable exception of the small basaltic group 

 of Gambier's and Pitcairn's Islands. 2 Volcanic rock, similar 

 to the latter, is also found in the same parallel (between 25 

 and 27 south latitude); 12 60 geographical miles farther to 

 the east, in the Easter Island (Waihu), and probably also 

 240 miles farther east, in the rocks Sala y Gomez. On 

 Waihu, where the loftiest conical peaks are scarcely a thou- 

 sand feet high, Captain Beechey remarked a range of craters, 

 none of which appeared, however, to be burning. 



In the extreme east towards the New Continent, the range 

 of the South Sea Island terminates with one of the most 

 active of all island groups, the Archipelago of Galapagos, 

 composed of five great islands. Scarcely anywhere else, on 

 a small space of barely 120 or 140 geographical miles in dia- 

 meter, has such a countless number of conical mountains and 

 extinct craters (the traces of former communication between 

 the interior of the earth and the atmosphere), remained 

 visible. Darwin calculates the number of the craters at nearly 

 two thousand. When that talented observer visited the 

 Galapagos in the expedition of the " Beagle," under Captain 

 Fitzroy, two of the craters were simultaneously in a state of 

 igneous eruption. On all the islands, streams of a very 

 fluid lava may be seen which have forked off into different 

 channels and have often run into the sea. Almost all are 

 rich in augite and olivine ; some of which are more of a trachy- 

 tic character, are said to contain albite 3 in large crystals. It 



3 Dana, p. 137. 



3 Darwin, Vole, hi., pp. 104, 110112, and 114. When Darwin 

 says so decidedly that there is no trachyte on the Galapagos, it is be- 

 cause he limits the term trachyte to the common felspar, i.e. to or- 

 thoklase, or orthoklase and sanidine (glassy felspar). The enigmati- 

 cal fragments imbaked in the lava of the small and entirely basaltic 

 crater of James Island contain no quartz, although they appear to rest 

 on a plutonic rock (See above, p. 367 et seq). Several of the volcanic 

 cone-mountains on the Galapagos Islands, have at the orifice a narrow 



