CHARACTER OF CHANNELS AND FLOW OF BELL RIVER. 245 



with a deposit of brown clay resting on till, and this section has a very 

 gentle northward slope. The stream here consists of long dead-water 

 stretches, broken by short chutes of a few feet fall where rocky ledges 

 under the superficial deposits cross its course. The width in the still- 

 water stretches is very irregular, but it averages about a quarter of a mile. 

 In some places it contracts to two or three hundred yards and flows with 

 an accelerated current between rocky shores. These contractions usually 

 terminate in a sudden widening. On sounding the still-water stretches 

 they were found to be unexpectedly deep, averaging from 30 to 40 feet at 

 low water. The river all along looks as if something were choking the 

 freedom of its flow, and even when the water is lowest, in summer, its 

 channel appears to be brimming full. Except at the narrow parts, it 

 seldom has any well denned banks. As a rule, the ground on either side 

 slopes gently to the river and the trees grow quite to the water's edge. 

 Although these slopes consist of soft earthy material, there is no uni- 

 formity in the rate of rise in going back from the river. The condition 

 reminds one of what takes place when a stream is suddenly dammed up 

 and the water floods into the uneven ground on either side. A cross- 

 section of the channel is like that of a ditch rather than an ordinary 

 river-bed. This condition is exceptional, and it has been rendered pos- 

 sible in the present case by reason of the low gradient of the river (about 

 two feet per mile, including the chutes), the soft nature of its bed and 

 banks, and its northward course. If we suppose the rate of slope to 

 have been a little greater when the river first cut a channel large enough 

 to accommodate itself through the soft deposits, and that afterward the 

 flow of the water was impeded by a decrease in the grade, we should 

 have the present state of affairs. 



At two places where this part of the river bends to the northwestward 

 it sends off channels on the southwest side into the level clayey county. 

 The uppermost of these forms an island 16 miles long. Where the water 

 leaves the main river at its head it takes a backward course, almost in 

 the opposite direction from the current of the parent stream, and it must 

 have been induced to fall off in that manner by some cause operating 

 subsequent to the formation of the original channel. 



At the foot .of this long island the river turns directly west for a few 

 miles, and in this interval two bays extend to the south. A new chan- 

 nel has been cut from the head of the uppermost across to the other, as 

 if in response to a new pressure of the water. 



Character of the tributaries. — If the flooded appearance, the irregular 

 width, and the abnormal depth of the above-described portion of the 

 main river be due to the cause supposed, we should expect to find the 

 same appearances in its tributaries from the southwest or along the line 



