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PRICE 



of former biogenous conditions. In the tropical regions where corals and mangroves are con- 

 spicuous, the biogenous coastal condition is widespread. 



The western or Gulf coast of Cuba [3], which was studied in part, is another steep young 

 mountain- making coast, but one without a continental shelf or coastal plain. The Cuban section 

 [3] and the Mexican sections [1 and 3] have not been included in the energy study because of 

 lack of detailed data. I have investigated the geomorphology of these coasts and classified some 

 of the shoreline types. 



Figure 2 : Map from the Coast and Geodetic Survey Journal. G. C. Mattison has given us 

 this nice contouring of the continental shelf off Texas. You will notice the shelf comes out 

 evenly and smoothly, and then (with a change of contour interval) curves down more steeply to 

 the very rough continental shelf slope. 



Notice the Rio Grande Delta. While it is only a small extension of the coastline of about 

 15 or 20 miles, there is a similar bending out of the depth lines all the way down to the con- 

 siderable depth of 100 fathoms. The profiles will show that this shelf seems to be broadly 

 down- warped. 



At the north, on the Brazos- Colorado Delta, there is a widening of the shelf which con- 

 tinues out to 10 fathoms. 



Figure 3 : Profile off Corpus Christi Pass. This is a typical profile of the northwestern 

 section of the continental shelf between deltas. At the shoreline is the short but very steep 

 offshore slope of the barrier islands which continues out through a zone which is slightly con- 

 cave, and then begins to be convex, the convexity extending down the slope of the continental 

 shelf. 



Figure 4 : Profile of the Rio Grande Delta. The preceding profile between deltas is shown 

 by the broken line. The comparison of the two profiles shows an extension of the shelf which 

 seems to be a filled terrace. It passes landward into what seems to be a cut terrace with large 



Figure 3. 



