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bars on it. It may seem incautious to compare two particular profiles without a large number 

 of others to check them, but I have drawn a number of others and these two are characteristic. 

 This figure shows the typical textbook cut-terrace and filled-terrace. There is more material 

 in the filled area than has been lost in the cut area. Deltaic deposits should account for the 

 excess. 



Figure 5: * Indicates erosion at the shoreline of the cut terrace of Fig. 4, This body of 

 clay on a sandy beach is rare here, but I have two or three photographs of the occurrence taken 

 by other people, although I have not seen it myself. This seems to be deltaic clay from a sub- 

 delta of the Rio Grande which protruded into what is now the Gulf. The shoreline in this par- 

 ticular area has retreated. This figxire shows that erosion of the delta is going on, and our 

 deduction of a cut-terrace is warranted in actual fact. 



Figure 6 : Typical profile off the northwest coast of the Gulf of Mexico (Big Constance 

 Bayou), showing again for comparison the Corpus Christi profile ajid a somewhat similar pro- 

 file off Panama City, Florida, east of the active Mississippi Delta. The comparison shows the 

 outbuilding that takes place where the Mississippi, Red, and subsidiary rivers enter the Gulf. 

 The outbuilding extends eighty miles to the steep continental slope. 



Figure 7 : Profile off Panama City in the Panhandle of Florida, shown as the second 

 broken line in Fig. 6. This is more or less the Corpus Christi type, with some built-up mate- 

 rial on the shelf, but not as smooth as the Corpus Christi profile. This figure exhibits the 

 typical sudden short descent off the sandy barrier island, and some bars or old deltaic de- 

 posits. The concave portion of the profile is about 18 miles long. 



Figure 8 : G. F, Jordan's published map of the new, very accurate contouring of the con- 

 tinental shelf slope off Florida. Note the De Soto Canyon and some lesser drains on the slope 

 and the great scarp at the base of the slope. The shelf has no sharp edge but is broadly and 

 smoothly bowed down. At the other side of the Gulf the contouring off the Corpus Christi and 



Figure 4. 



*This figure was not available for publication. 



