24 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



headed in Lincoln County, Ark., between Meroney and South Bend, 

 where the delta of the Arkansas River was 20 miles wide. 



Outside of the Mississippi Valley, another long, narrower bay 

 extended up the drowned Red River Valley from Alexandria, La., to 

 a head above Shreveport. 



The bayous in western Arkansas County and eastern Jefferson 

 County in Arkansas occupy former tidal marshes whose shore follows 

 the 170-foot contour line on the Gillett quadrangle. A 10-foot scarp 

 3 miles southwest of Gillett leads up to the Coharie terrace. 



The name Sunderland terrace dates from 1901, when it was pro- 

 posed by Shattuck (1901, p. 102). The name is taken from a hamlet 

 in Calvert County, Md. As described by Shattuck the Sunderland 

 is a marine terrace having a shore line about 170 feet above sea level. 

 In later work Shattuck (1906, p. 68) included parts of several terraces 

 in the Sunderland, which he thought had been warped. According 

 to Cooke (1931, p. 507) "The name Sunderland should be restricted 

 to the terrace that is bounded by the shore line at or near 170 feet 

 above sea level." 



The Sunderland appears to be the same as Fisk's (1938a, p. 56) 

 Montgomery terrace, which lies within a former estuary of the Red 

 River. The type locality of this terrace is at the intersection of U. S. 

 Highway 71 and State Highway 162 near Montgomery, Grant Parish, 

 La. The altitude of this intersection as shown on the map of the 

 Montgomery quadrangle is approximately 170 feet above sea level. 

 The 20- foot contour interval on the map is too great to show the 

 exact location of the shore line. 



The withdrawal of the Gulf from 170 feet to a lower level drained 

 the flooded valleys and exposed the Sunderland terrace. 



Okefenokee terrace {shore line 145 feet). — The approximate loca- 

 tion of the shores of the Okefenokee bay is shown in figure 12. At 

 the 145- foot stage the Mississippi Valley was drowned as far north 

 as the thirty-fourth degree of latitude, that is, to Tallahatchee and 

 Bolivar counties in Mississippi. In Arkansas tidewater extended up 

 the White River even farther north, to the vicinity of St. Charles. 

 The western shore of the estuary through Arkansas was fairly straight 

 between St. Charles and the Louisiana border. Below Selma, in Drew 

 County, it lay west of Bartholomew Bayou. In Louisiana it followed 

 the western side of the Ouachita Valley as far as Harrisonburg, be- 

 yond which it passed southwestward to the Gulf of Mexico. A profile 

 across the Okefenokee terrace at Bastrop, La., is shown in figure 13. 



