626 OREGON. 
the vicinity of the lofty cones of the Cascade Range, and elsewhere 
throughout the territory. The region more especially thus charac- 
terized, includes the greater part of the inner section, and the Colum- 
bia River, Willammet and Cowlitz districts in the coast section. But 
beside basaltic rocks, there are, in the districts last mentioned, tertiary 
sandstones and shales, and basaltic conglomerates, prevailing to a 
very large extent, and continuing some distance—the limits yet un- 
determined—up the Columbia. There are also granitic and allied 
rocks along with serpentine, besides some ancient conglomerates and 
shale in the Umpqua and Shasty regions, and in different parts of the 
Cascade and shore ranges at a distance from the volcanic peaks. Be- 
fore entering upon the description of these rocks, we may glance at 
their geographical distribution, as far as ascertained by the observa- 
tions of the writer and others connected with the Expedition. 
The tertiary rocks were first seen on the Columbia in the vicinity 
of Astoria. They occur along the shores of this river for twenty miles 
from the sea, though occasionally interrupted by basalt, as at the 
settlement Astoria. They were met with over the country south of 
this part of the Columbia, on a jaunt to Swalalahos; but among the sand- 
stone hills of this region were others of basalt; and Swalalahos itself 
is the remains of an ancient volcanic mountain or crater, consisting 
principally of volcanic conglomerate. ‘These sedimentary deposits, 
according to the reports of the officers of the Vincennes, prevail to the 
north of the Columbia, and upon the shores of Puget’s Sound. They 
were observed by the writer ten miles north of the Columbia, in a 
stream emptying near Gray’s Bay. 
Above the lower twenty miles of the Columbia, the banks are 
mostly basaltic ; and in some places these rocks constitute a long wall 
or palisade, nearly bare, from one to three hundred feet high. Basalt 
continues to be the rock of the river, except where the shores are 
alluvial, as far as the forks, though for a portion of the distance it is 
interstratified with basaltic conglomerate or tufa. Alluvial shores 
occur for a long reach above the mouth of the Willammet. ‘Twenty 
miles east of Vancouver the basalt begins again to line the river, and 
six miles beyond it stands out in needles and slender cones, forming 
what is called Lower Cape Horn. At the Cascades, forty-five miles 
from Vancouver, the basalt, as shown by Mr. Drayton’s specimens, is 
very cellular, and in some places a scoriaceous lava. Both here and at 
the Dalles, the basaltic rocks, as I am informed, are associated with 
basaltic conglomerate. Thirty-five miles above the Dalles, commences 
