650 STEVENSON— FORMATION OF COAL BEDS. [November 3, 



At the time of the early settlements, the foot of the raft was at 

 Natchitoches, 120 or 130 miles from the Mississippi. 



Humphreys and Abbot,^^ writing in 1861, reported that the raft 

 was an enormous accumulation of drift logs, some floating, some 

 sunken. The rotting of the logs at the lower end and fresh acces- 

 sions at the upper end led to advance up stream at the rate of from 

 one mile and a half to two miles each year, while the retreat at the 

 lower end was about equal to the gain above. At one time, the 

 lower end was at Natchitoches but in 1854 it was at 53 miles above 

 Shreveport, a retreat of about 150 miles. At that time, it was nearly 

 13 miles long. Above Shreveport to the raft, the river bed was 

 strewn with logs, stumps and other vegetable debris. The river is 

 very shallow, 3 to 4 feet deep at low water, and it was about 220 

 yards wide at the head of the raft, 405 miles from the Mississippi. 

 Rotting would cause the 13 miles, reported by Humphreys and 

 Abbot, to disappear within seven or eight years. 



The notes given by Humphreys and Abbot were from a casual 

 examination by their assistant, the matter lying outside of the scope 

 of their work. The raft was a serious obstruction to navigation, 

 cutting off the region above from communication with the Missis- 

 sippi. Congress in 1871 ordered a complete survey, which was made 

 by Lieutenant Woodruff, whose report, rendered in 1872, gave the 

 first exact information respecting the actual conditions. Captain 

 Howell,^" in transmitting the report, remarks that the facts have 

 been misapprehended even by engineers. " The ' great raft ' itself 

 dwindles to a mere pigmy in comparison with the popular notion of 

 its extent and composition." Woodruff, in 1871, proved that the 

 raft extended along the river for about seven miles, but that through- 

 out that distance the channel is only partially obstructed. The whole 

 mass of floating raft was but 290 acres and the whole area of " tow- 

 heads " or raft resting on the bottom was 103 acres. The towheads 

 are formed during freshets by accumulations of logs and drift around 

 a " snag." As the water falls, the pile rests on the bottom and a 



^'A. A. Humphreys and H. L. Abbot, "Physics and Hydraulics," etc., 

 1876, pp. 21-23. 



^'C. W. Howell, 42d Congress, 2d Session, Exec. Doc, 76. p. i. 



148 



