Southern Appalachian Digital Collections

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Glimpses of our National Monuments

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Item’s are ‘child’ level descriptions to ‘parent’ objects, (e.g. one page of a whole book).

  • 40 OUR NATIONAL MONUMENTS decreases to a terminus about 50 feet from the entrance, forming a sort of half dome. There is a spring in the farther recess of the cave which forms a stream that winds its way around the edge of the cave and sinks into the sand at its mouth. The vista looking into the canyon from the depths of the cave is a magnificent one. The natural bridges are the result of stream erosion in an elevated region. Doubtless thousands of similar bridges have been formed and destroyed in past ages, and many more will be made and later destroyed in the ages to come. The sandstone in which these bridges were cut resulted from a great sand deposit laid down long ago near sea level, and later covered with thousands of feet of sediments of various kinds. After being buried for millions of years, this sandstone and the overlying rocks of the plateau were raised and the elevated surface exposed to erosion. Then, as now, the rain formed rills, rivulets, and rivers. These cut into the slowly rising surface of the rocks, and valleys of various kinds were developed. In general, where the rise was slow, and especially where soft rocks were present, broad shallow valleys were eroded; and where the rise wras relatively rapid, or the rocks hard, deep narrow canyons were cut. The form was also influenced by the rate of elevation of the region, which varied from time to time, and when the uplift was slow or had ceased the streams tended to broaden their valleys and to meander widely over the evenly graded bottom lands. In this way White Canyon was eroded, and as the surface rose these streams cut their channels deeper and removed the rocks at the sides. During the long ages that these processes were acting thousands of feet of rock was removed from the plateau region. In the course of its down-cutting the little stream which carved White Canyon meandered widely, carrying away the soft material of the red rocks that once covered the white sandstone. When in its downward course it reached this hard sandstone it found erosion more difficult. But its meandering course was established, and it cut its trench into the sandstone along its previously determined course. Its lateral cutting continued, but little headway was made toward broadening the canyon in the hard rock. Thus were formed the intrenched meanders, such as those at Caroline and Augusta bridges. At each of these two bridges the stream in its meandering course formed a loop resembling an oxbow and flowred about a peninsula of rock which had a narrow7 neck. This neck was at the point where the stream was obliged to turn sharply in order to flow around the end of the peninsula. Also on its return to the other side of the neck, it made a sharp turn in the opposite direction. It is the law of streams that they cut into, their banks on the outer side of curves.
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Object’s are ‘parent’ level descriptions to ‘children’ items, (e.g. a book with pages).