ig. EAST FLORIDA FLATWOODS. 329 



have caved in.* South of Waldo the topography is a little undu- 

 lating, and may indicate somewhat different geological conditions. 



The most striking topographic feature of the region is Trail 

 Ridge, which extends from a few miles west of Jesup, Georgia, 

 southward parallel to the coast and about forty miles distant from 

 it, until it merges with the western edge of the lake region. (It is 

 indicated by a dotted line on the map.) Its summit is said to be 

 210 feet above sea-level at Highland, and 238 feet east of Starke. f 

 Its origin has never been satisfactorily explained. In Florida it 

 coincides for some distance with the Atlantic and Gulf divide, but 

 that is probably merely accidental, for it has no such relation irij 

 Georgia. 



About fifteen miles east of Trail Ridge, and parallel to it, both 

 in Georgia and in Florida, is another ridge so low that a person not 

 specially looking for it would hardly notice it; J but in some ways 

 it seems more significant than Trail Ridge. For it causes the Satil- 

 la and St. Mary's Rivers to flow parallel to the coast for many miles 

 just before they break through it, and the marly spots mentioned in 

 a preceding paragraph nearly all lie east of it. 



The stream valleys are mostly narrow and but little depressed 

 below the general surface, though in some of them there is a slight 

 development of the same sort of rolling topography that character- 

 i;^es the West Florida pine hills. Springs are rather scarce, but 

 there are a few large limestone springs, of which Green Cove 

 Springs, in the town of the same name, is probably the best known. 

 The streams are practically all cofifee-colored, bordered by swamps, 

 and not subject to much fluctuation. The St. John's River is nota- 



*Probably the most noted of these sinks is the "Devil's Millhopper," in 

 Alachua County, about three miles west of Paradise or six miks northwest 

 of Gainesville. It is over 100 feet deep, nearly circular, and surrounded by 

 level flatwoods. For additional notes on it, see Dall, U. S. Geol. Surv. Bull. 

 84:108- 1892; Vaughan, U. S. Geol. Surv. Min. Res. 1901:932. 1902; Sellards, 

 Fla. Geol. Surv. Bull. 1:29. 1908; Matson & Clapp, Sellards & Gunter, 2nd 

 Ann. Rep. 71-72, 288. 1910; Sellards, 4th Ann. Rep. 34-35- 1912. 



tin U. S. Geol. Surv. Bulletin 516, p. 17 (1912), the elevation of a point 

 2.6 miles northwest of Lake Kingsley, which must be on or near the summit of 

 Trail Ridge, is given as 238.382 feet. This agrees remarkably well with a 

 statement by Dr. W. I. Burnett in Am. Jour. Sci. 67:408 (1854) that a point 

 "one mile west of Kingsley's pond and seven miles east of Sampson's pond" is 

 237V2 feet above low tide. 



jFor references to previous literature relating to this ridge see Bull. Torrey 

 Bot- Club 38:230. 1911. The Georgia end of it has since been described (as 

 a terrace) by Otto Veatch in Geol. Surv. Ga. Bull. 26:36, 426, 434. (Jan. 1912). 



