Fossil Flora of the John Day Basin, Oregon, Ausgaben 204-210

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U.S. Government Printing Office, 1902 - 153 Seiten
 

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Seite 124 - LIBRARY CATALOGUE SLIPS. [Take this leaf out and paste the separated titles upon three of your catalogue cards. The first and second titles need no addition; over the third write that subject under which you would place the book in your library.] United States.
Seite 102 - In attempting to work out the bearing of the plants above enumerated on the question of the age of the beds it should not be overlooked that any conclusions drawn might be quite different from what they would be were the whole flora of each of the localities to be considered.
Seite 15 - The regions of the John Day River and Blue Mountains furnish sections of the formations of central Oregon. Above the Loup Fork or Upper Miocene there is a lava outflow, which has furnished the materials of a later lacustrine formation, which contains many vegetable remains. The material is coarse, and sometimes gravelly, and it is found on the Columbia River, and I think also in the interior basin. Professor Condon, in his unpublished notes, calls this the Dalles Group.
Seite 19 - II, p. 127. in part of the same age, but may have accumulated in a different basin. At Rattlesnake Creek near Cottonwood the Mascall is not less than 800 to 1,000 feet thick. The beds are made up largely of ash and tuff and are generally light colored, though there are some brownish and reddish strata. Coarse detrital materials are generally absent from the typical section on the north side of the East Fork Valley.
Seite 20 - ... formation are such that it could not be older than early or middle Pliocene, while the amount of erosion which took place between the close of this epoch and the middle or latter part of the Quaternary shows that it could not possibly be later than Pliocene. QUATERNARY. Terraces. — At numerous points along the John Day and its tributaries, one or more terraces are to be found not far above the existing floor of the valley.
Seite 10 - Mountains, whose rugged eastern ridges rise to a height of over l5,000 feet, those to the west being lower and made up largely of Tertiary lavas, which form regular and often flat-topped ridges. John Day River, with its numerous branches and tributaries, draining an area of approximately 10,000 square miles, has a general westward course through the basin, which it leaves on its west side through a gap between the north and south ranges of the Blue Mountains; thence its course is north to the Columbia....
Seite 16 - Taxodium nearly resembles that from the shales at Osino. Nevada, and on various grounds I suspect that these beds form a part of the Amyzon Group (American Naturalist, June, 1880).
Seite 40 - ... of them under this form. If Newberry's elastic species was maintained it would be polymorphous enough to include them all, but I do not think it will adequately represent the facts to do so. In regard to Lesquereux's point of view, it may be said that if extreme examples were selected it might seem logical to call them species, but when the whole are grouped together it is found absolutely impossible to draw any satisfactory line between them. Take, for example, the question of shape. The narrowest...
Seite 18 - ... it into several fairly well-marked divisions. Wherever the John Day is well exposed in the central and western portion of the basin, it seems to be divisible into three stages, which have been designated* the Lower, Middle, and Upper John Day. The lower division consists usually of highly-colored shale, which breaks down readily, forming characteristic mud-covered domes. These beds are in the main a deep red, with occasional alternating strata of buff or white ash.
Seite 16 - ... study. Opposite the Powell place, four or five miles above Ritter, on Middle Fork, fossiliferous middle Tertiary beds rest upon the older series. Columbia lava here covers the fossil beds and also laps over upon the diorite, from which it is separated by only a thin bed of ash. At Spanish Gulch, twelve miles southwest of Dayville, the Chico Cretaceous is seen resting upon serpentine, which has the appearance of being intruded into it. At the head of the gulch the serpentine is separated from...