22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I49 



Ozark Escarpment from Bradford (Augusta quadrangle) to the 

 Jackson-Independence County line (Newport quadrangle). Thence 

 it wanders eastward around delta deposits to Bott Spur, 3 miles west 

 of Wynne in Cross County. From this point southward on the Wynne 

 quadrangle there is a low scarp bordering the Hazlehurst terrace, 

 which separates it from Crowley Ridge (fig. 6) . 



The name Coharie Formation, derived from Great Coharie Creek, 

 a tributary of Black River in North Carolina, was applied by 

 Stephenson (1912, p. 273) to terrace deposits whose upper surface 

 ". . . forms a terrace plain more or less dissected, which slopes from 

 elevations of about 160 or 170 feet along its southeastern edge to 

 elevations of about 230 or 235 feet along the foot of the escarpment 

 which separates it from the Lafayette belt" (Stephenson, 1912, p. 

 274). These upper limits are a little too high. The shore line of 

 the Coharie was later placed at 215 feet above sea level by Cooke 

 (1930a, p. 391; 1930b, p. 582; 1935, p. 333; 1936, p. 132), who 

 has traced it through every state from New Jersey to Florida (manu- 

 script maps). 



The Coharie terrace is evidently the same as the Bentley terrace 

 of Fisk, which ". . . slopes southward at a rate of 5 feet per mile from 

 215 feet above sea level, at the foot of the escarpment near Bentley, 

 to 180 feet at the Grant-Rapides Parish line" (Fisk, 1938a, p. 60). 

 This area occupies part of the combined estuaries of Red River and 

 Little River. 



After a long still stand at 215 feet, the sea withdrew to an unde- 

 termined lower level and came to rest at or near 170 feet, exposing 

 the Coharie terrace. 



Sunderland terrace {shore line 170 feet). — At this lower, 170-foot 

 stage of the Gulf, the boundaries (fig. 11) of the lower reaches of 

 the embayment did not differ much in location from the higher 

 stages. Where they had lain near high escarpments only a narrow 

 strip of the Coharie emerged. The greatest changes were in the upper 

 parts of the bay (figs. 9, 10) where the drowned valley was shallower 

 and the drop of 45 feet laid bare a greater width of bay bottom. The 

 shore at the head of the bay became very intricate, for the Mississippi 

 River built a delta, which extended southward from Helena, Ark., 

 almost to Clarksdale, Miss. 



An arm of the Sunderland bay extended up the drowned valley 

 of White River to a head above Clarendon, Ark. Its mouth at St. 

 Charles in Arkansas County was about 12 miles wide. Another branch 



