HYPSOMETEIC ADDENDA. 283 



ward of the Rio Grande del Norte ; for example, in Taos. 

 (Compare Abert's Examination of New Mexico, in the Do- 

 cuments of Congress, No. 41, pp. 489 and 581 605, with 

 my Essai pol. T. ii. pp. 241 244.) The Sierra Nevada of 

 California is parallel to the Coast of the Pacific ; but between 

 the latitudes of 34 and 41, between San Buenaventura 

 and the Bay of Trinidad, there runs, on the West of the 

 Sierra Nevada, another (smaller) coast chain, of which Monte 

 del Diablo, 3448 French, 3674 English feet high, is the 

 culminating point. In the narrow valley, between this 

 coast chain and the great Sierra Nevada, flow from the south 

 the Rio de San Joaquin, and from the north the Rio del 

 Sacramento, on the banks of which, in rich alluvial soil, are 

 the rich gold-washings now so much resorted to. 



I have already referred, p. 43, to a hypsometric levelling, 

 and to barometric measurements made from the junction of 

 the Kanzas River with the Missouri to the Pacific, or 

 throughout the immense extent of 28 degrees of longitude. 

 Dr. Wislizenus has now successfully continued the levelling 

 began by me from the city of Mexico, in the Equinoctial 

 Zone, to the North as far as Santa Ee del' Nuevo Mexico, 

 in lat. 35 38'. It will be seen, perhaps, with surprise, 

 that the elevated plain which forms the broad crest of the 

 Mexican Andes is far from sinking down, as had long been 

 supposed, to an inconsiderable height. I give here for the 

 first time, according to the measurements which we at present 

 possess, the elevations of several points, forming a hue of 

 levelling from the city of Mexico to Santa Ee, which latter 



