THE FLOOD OF 1 843. 3! 



site to the bridge, was two feet nine inches above the level of 

 the floor of the bridge, while the water on the floor of the 

 bridge was at least three feet six inches high. This shows 

 that the water at the bridge, near the middle of the flood, was 

 nine inches higher than at the margin. Forty yards below 

 the bridge, on the margin of the stream, the water stood one 

 foot lower than the level of the floor of the bridge. At forty- 

 three yards above the bridge, on the margin of the flood, the 

 water was three feet higher than the level of the floor of the 

 bridge. The floor of the bridge is seven feet three inches 

 above low water. The fall in the creek for one hundred and 

 eighty yards above the bridge is .16 of an inch to the yard, 

 and for two hundred and forty yards below the bridge, the 

 fall is .12 of an inch to the yard. The width of the valley 

 of the creek occupied by the flood at the bridge, is sixty-four 

 yards. The width of the valley below the bridge, at the nar- 

 rowest place at high water mark, is eighty-six yards, from 

 which point the valley continues to widen for some distance 

 below. 



From these measurements it would appear that the bridge 

 occupied a position, below which the valley of the creek sud- 

 denly expanded, and consequently the same volume of water 

 in passing down could not remain at the same elevation below 

 as it did above the bridge, by nearly four feet, according to 

 the foregoing data. 



It has been before stated, that forty-three yards below the 

 bridge, the high water mark on shore was one foot below the 

 level of the bridge, and it was also stated, that the middle of 

 the current, at the bridge, was nine inches higher than at the 

 margin ; but it is probable that in consequence of the valley 

 becoming wider, the middle of the current, forty-three yards 

 below, would not stand so many inches above the height at 

 the margin. There must, therefore, have been a great defici- 

 ency of water below the bridge to counterbalance that which 

 was above and that which rested upon it. The length of the 

 platform of the bridge is thirty-six feet, its breadth fourteen 



