GEOLOGY BETWEEN APALACHICOLA AND OCKLOCKNEE RIVERS. 33 
Mr. Arthur Pew. The levels at intervening points on the river 
between River Junction and Blountstown are obtained approxi- 
mately by averaging the fall in the water level of the river from 
River Junction to Blountstown. On the Ocklocknee. river, approx- 
imate levels have been obtained by utilizing levels on the Seaboard 
Air Line railway and on the Georgia-Florida and Alabama rail- 
way, which have been kindly supplied by these two roads. 
The highest exposure in the Chattahoochee Landing section 
recognized as representing the Chattahoochee formation is at an 
elevation of 85 feet above the river. The water level in the river 
at the time this section was made was about 51 feet above the sea.* 
Accordingly the top of the Chattahoochee formation, as nearly as 
can be determined, is about 136 above, sea at this exposure. 
At Aspalaga Bluff the water level in the river is estimated to be 
about 5 feet lower than at the railroad bridge at River Junction. f 
In this section limestones apparently of the Chattahoochee forma- 
tion are exposed to an elevation of 63 feet above the rirver, or no 
feet above sea. 
Rock Bluff is 12 miles in a direct line down the river from 
River Junction, and the water level in the river at this bluff was 
estimated to be about 8 feet lower than at River Junction, or 42 
• feet above sea.t The Chattahoochee limestone in this bluff stands 
about 10 feet above water level, the top of the formation at this 
place being apparently about 52 feet above sea. 
On the Griffin place, about 2 miles below Rock Bluff (S 31, 
* At the time this section was made in 1909 the gauge on the bridge at 
River Junction read 7C feet. Since that time, however, the bridge has been 
rebuilt. The bottom; of the present gauge is about 43^2 feet above sea level. 
Assuming that the gauge on the new bridge was placed at approximately the 
same level as on the old bridge, the water level at the railroad bridge on March 
5, 1909, was about 51 feet above sea level. Chattahoochee Landing is less than 
one mile above the railroad bridge, hence the water level differs by probably 
less than one-half foot from that at the bridge. Accordingly, as an approxi- 
mate measurement, it is assumed that the water level in the river at the time 
this section was made was about 51 feet above sea. 
tOn March 5, 1918, the water level n the river at River Junction was 48.6 
feet above sea. On the same date the water level in the river at the landing 
at Blountstown was 35.4 feet, indicating a fall in water level of 13.2 feet from 
River Junction to Blountstown, a distance in a direct line of about 20 miles. 
The average fall of the river in this part of its course is therefore approxi- 
mately .65 feet per mile. 
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