Page:Oregon Historical Quarterly vol. 6.djvu/177

171 JOURNAL OF A VOYAGE TO N. W. AMERICA. 171 to the size of a cannon ball. They are much harder than the rocks in which they are contained & resist for a much longer time the action of the weather. On some parts of the rocks I detected a white efflorescence, but in such small quantities that I could not detect its composition ; it was, however, insipid. The water that issued through this magnesian limestone deposits some ferruginous mat- ter, indicating that a small portion of iron enters into the composition of the rock. The limestone is traversed by veins of two different substances, sandstone & carbornate of lime, in the form of spar. The calcareous veins are very small, not above 4 inches in breadth. Their occurrence is by no means frequent, the only place where I saw them was near Cape Dissapointment. The standstone veins ar very common on the side of the river. This sandstone is of a very coarse, granular texture, & is soft & friable. These veins are about the breadth of 3 feet in general & have little inclination. They resist the action of the air longer than the limestone, as in many places the lime- stone is washed away & the more durable veins remain like small dykes. The fossil contents of this rock, although not very varied, are abundant. They consist as far as my examination extended entirely of shells. A [illegible] of large size and good preservation was by no means un- common. The handsomest shell may probably [be] a spe- cies of Venus. Those parts of the rock that were unusually hard were the richest in this shell ; but easily fell out en- tire from a smart blow of the hammer. I also found great abundance of a small species of, & very imperfect fragments of a species of Solen. Such is the geological structure of the country about Ft. George as far [as] my observations extended. But from the limited opportunity I had of penetrating far into the interior of the country, of course it was only in my power to give a general idea of its geology, & not to enter into those interesting details,