This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...The terraces found at the lower end of the Coamo, and to a less extent associated with the other streams, are due to the dissection of the embayed portions of the coastal plain. The elevation of about 250 feet which brought the coastal plain to view revived all the streams. The reviving influence of uplift took place ...
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1920 Excerpt: ...The terraces found at the lower end of the Coamo, and to a less extent associated with the other streams, are due to the dissection of the embayed portions of the coastal plain. The elevation of about 250 feet which brought the coastal plain to view revived all the streams. The reviving influence of uplift took place long enough ago that the effect is now active in the headward courses of such streams as the Eio de la Lapa. In the upper reaches of the streams degradation is cutting into the old complex of volcanic rock. Figure 23 shows how the Eio de Coamo has cut a young valley 50 feet deep into the alluvium accumulated when the Coamo stood at the highest level during recent times. Most of the streams in this district have cut laterally faster than they cut downward. This lateral cutting flattens the floor of the valley. The Fig. 22.--Valley of the Ouamani Photographed by Professor Charles P. Berkey. cut continues to one side until the streams meets a resistant rock which reflects it to the opposite side, and a deflection in a stream once started continues until deflected again. Associated with lateral cutting is downstream cutting. The combined effect is to produce a terrace. Slow uplift of streams which are provided with rocks in their banks to deflect them will cause a series of terraces to be cut one below the other. Ledges of rocks projecting into the stream are ideal for this purpose. The Eio de Coamo is deflected by the Coamo Springs limestone and as a result three terraces are formed. Continued uplift has caused these to be dissected by consequent streams into a dendritic pattern. The highest terrace of the Coamo is dissected to a depth of 50 feet in this way--a testimony to the rapid rejuvenation which has taken place. The coastal pattern appears ...
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Add this copy of Geology of the Coamo-Guayama District... to cart. $47.03, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2012 by Nabu Press.
