404 COSMOS. 



ot* longitude. On the American continent, near the sea- 

 shore, a number of more or less active volcanoes has become 

 known to mariners within the last seventy or eighty years, 

 but this group lay hitherto as it were isolated, and uncon- 

 nected with the volcanic range of the Mexican tropical 

 region, or with the volcanoes which were believed to exist 

 on the peninsula of California. If we include the range of 

 extinct trachytic cones as intermediate links, we may be 

 said to have obtained insight into their important geo- 

 logical connection over a gap of more than 28 of latitude, 

 between Durango and the new Washington territory, north- 

 ward of West Oregon. The study of the physical condi- 

 tion of the earth owes this important step in advance to the 

 scientifically well-prepared expeditions, which the govern- 

 ment of the United States has fitted out for the discovery 

 of the best road from the plains of the Mississippi to the 

 shores of the South Sea. All the departments of natural 

 history have derived advantage from those undertakings. 

 Great tracts of country have been found, in the now ex- 

 plored terra-incognita of this intermediate space, from very 

 near the Rocky Mountains on their eastern slope, to a great 

 distance beyond their western descent, covered with evi- 

 dences of extinct or still active volcanoes (as for instance 

 in the Cascade Mountains). Thus, yetting out from New 

 Zealand and ascending first a long way to the north-west 

 through New Guinea, the Sunda Islands, the Philippines 

 and Eastern Asia, to the Aleutians, and then descending 

 towards the south through the north-western, the Mexican, 

 the Central American, and South American territories to 

 the terminating point of Chili, we find the entire circuit 

 of the basin of the 'Pacific Ocean, throughout an extent of 

 26,400 geographical miles, surrounded by a range of recog- 

 nisable memorials of volcanic action. Without entering 

 into the details of exact geographical bearings and of the 

 perfected nomenclature, a cosmical view such as this could 

 never have been obtained. 



Of the circuit of the great oceanic 9 basin here indicated 

 (or, as there is but one united mass of water over the 



9 The term "Grand Ocean/' used to designate the basin of the 

 South Sea by that learned geographer, my friend Contre-Amiral de 

 Fleurieu, the editor of the Introduction Historique au Voyage dt 



