Southern Medical and Surgical Journal - Georgia Regents University

1859.] Climate to the Consumptive, &c. 725of small mountains. Another noticeable distinction which resultsfrom the respective changes of these two mountain ranges,is the destruction ofthat great valley formation between them,which characterizes the topography of the State of California.From the point of reappearance of the Coast Range, to the ColumbiaRiver, and between the two systems of mountains, thereis an imperfect valley formation, the Willamette Yalley, themeagre representative of the great conjoined valley to the south,whose impressibility of climate is not to be compared with thelatter.Looking to the interior, we also descry some differences inlocal topography worthy of notice. Here, the great Columbiawith its forming streams, the Lewis and Clark Rivers, embracingwithin the limits of their origin, the entire extent of the territoryto the Rocky mountains, instead of seeking a southern outlet,as does the Great Colorado River, assumes at the centre of thearea, an almost due-west direction to the Pacific, passingthrough the Cascade Range. Again ; near the junction of theSierra Nevada, and the Cascade Range, there is a mountainousextension almost at right angles to them, which reaches acrossWashington Territory, nearly to the Rocky mountains. TheBlue mountains of Oregon are also connected with this latterbranch, and they together constitute that elevation of the southernpart of the territory, which both yields the precipitation ofthe Lewis or Snake River, and determines a northward flow ofits waters.Besides these, there arematerial differences in the altitude ofdifferent parts of this interior. Its southern part continues thegreat elevation of the plateau of the Great Basin, but towardsits centre, the altitude greatly diminishes to about eight hundredor a thousand feet, with inclined planes extending to the surroundingmountain bases. In this central depression is thejunction of the two rivers already mentioned, the point at whichthe Golumbia River isformed.A remaining field for an inspection of local differences of climate,is the circulation of the Pacific waters. We have seenthat the distinctiveness ofthe climate of California is to a greatextent attributable to a peculiar circulation of the ocean itself.Wherefore we are led to enquire whether similar peculiarities