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Fossil Tree Trunks in Petrified Forest, Specimen Ridge. Yellowstone Nat. Park, Wyo.

posted on 21.05.2019, 00:00 by No Author
FOSSIL TREE TRUNKS IN PETRIFIED FOREST, SPECIMEN RIDGE, YELLOWSTONE NAT. PARK. The picturesque valley of the Lamar River is defined on the S. by Specimen Ridge, a remarkable survival of the epoch of volcanic activity in the Park. Along its steep slopes, for a distance of 7 or 8 miles, great numbers of fossil tree trunks, standing erect as they grew, have been weathered out from the mountainside. Countless centuries ago these trees were entombed and later fossilized by the outpourings of lava and ash from the volcanoes which were then active in the Park area S. of Specimen Ridge. Fossilization has preserved in these trees the msot minute details of the living wood. Geologists have found on this ridge 12 successive strata of forests, one above another, and 12 layers of volcanic scoria between them, indicating that in the course of thousands of years, at least, this number of forests grew up, to be successively overwhelmed by eruptions. Of the four fossil trunks which we see below us, the largest, on the right, is that of a great redwood, 26.5 ft. in circumference. the three lower ones are pines, from 2 to 3 ft. in diameter and about 25 ft. high. The weathered lava deposits in which they were imbedded are plainly visible all around them. Far below us in the valley of the Lamar River may be noted the grinding effects of a great prehistoric glacier discernible in low, rounded hills and shallow depressions now filled with small lakes. We can also see the many huge bowlders which were borne down from the mountains by the glacier and left scattered in confusion over the floor of the valley when the ice melted away. (View looking N. Elev. 7,500 ft. Lat. 45° N.; Long. 111° W.)



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