388 Observations on the Physical Geography 



But in the vicinity of the sea the country instead of being open 

 prairie is covered with forests of evergreens. In Oregon these 

 prevail over the larger part of a breadth of thirty miles along 

 the coast. In the vicinity of Astoria, as has been mentioned 

 by various travellers over the region, the trees of the dense 

 woods are extremely large — two hundred and fifty to three hun- 

 dred feet being a common height. In July, 1841, on an excur- 

 sion to Mt. Swalalahos, twenty-five miles south of Astoria, we 

 travelled over a heavily timbered undulating country, passing 

 trees occasionally twenty-five feet in circumference ; and one 

 measured was thirty-seven feet. In some places the fallen trunks 

 of trees (pines, hemlock, spruce, and alders) so obstructed the 

 way, that we were compelled to travel upon them, passing 

 from one to another, seeing the ground ten to fifteen feet below 

 us. The soil was generally good, and supported a thick growth 

 of underbrush. There were flats near Chishuk's river, but they 

 were covered with forests. 



The country of the Western Section is thus divided longitu- 

 dinally into a forest and prairie portion, the former densely 

 ivooded, the latter bearing only scattered oaks, and lines of forest 

 along the streams. Yet in these prairie districts, elevations over 

 one thousand feet high are wooded like the coast region, and the 

 forests extend down their slopes, especially the northern and 

 western, nearly or quite to their bases. Elk mountain and the 

 Umpqua ridges were thus densely clothed with forests. 



Beyond the Cascade Mountains, in the Eastern Section, even 

 the ibrest-border to the rivers fails to a considerable extent, and 

 the woods are confined to still higher ridges. And beyond the 

 Blue Ridge, to the summits of the Rocky Mountains, there are 

 few arable spots in a region of wide sterility. 



North of the Columbia this coast i gion of forests widens, 



while to the south it gradually narrows. Near Francisco Bay 



the lower hills are mostly bare of trees, or support only grass and 



shrubbery. Only the ridges of the coast range, a thousand 



feet in altitude and higher, are well wooded, and produce the 



famous cedars of the region. Going iarther south, the forests 



of the ridges are confined to those of still greater height; and 



in the California!) Peninsula, as travellers affirm, the mountains 



are bare to their summits. The region is a collection of lofty 



ridges, wild and ru; jed, overrun with rocks and sand, and mostly 



bare of verdure. The Cerro de la Giganta is 4,500 to 5000 feet 



high. Only two small streams enter the sea on the west, and 



none on the east. Humboldt says, where there is soil there is no 



water, and where water, nothing but rocks. 



Thus whether we recede inland from the coast, or southward 

 along its course, forest vegetation gradually diminishes ; while 



going northward it increases in extent. The lower lands are 



