Butterfield : Notes on the Growth of Spurn. 327 



Between the channel of the Humber and Kilnsea are huge 

 stretches of clay foreshore, and this in addition to the land at 

 Kilnsea would have to be cut throug^h down to low water level 

 before any great alteration could be made to the Humber 

 channels. 



Closely allied with this coast erosion is the question of the 

 origin of the mud in the Humber, and since Poulson wrote in 

 1849 that it came from the coast of Holderness he has been 

 frequently quoted. 



The writer has personally gone into the subject, and he is 

 satisfied from the results of his own experiments that the 

 opposite is the case.'''=" 



The duration of the ebb compared to the flood is so great 

 that it would be impossible for any material to work up against 

 it. At Hull the ebb runs 7^ hours and the flood five hours, 

 and material in suspension in the Humber at Hull would be 

 II miles nearer Spurn after one complete ebb and flood than it 

 was before, taking into consideration the relative velocities. 



The flood tide is the great scouring agent, but it is the ebb 

 tide which is the predominant factor in conveying any eroded 

 material out to sea, as it has the increased velocity due to the 

 fresh water. 



Again, the cliff's of Holderness are not reached by the tide 

 until close upon high water, and before any eroded material 

 could find its way into the Humber the ebb would have com- 

 menced, and the direction of the tidal currents at Spurn are 

 such, that it having once been carried from the Humber mouth 

 it could never return to it again. 



Analysis of Humber waterf shows that at Spurn there is 

 very little silt but a large quantity of salt, whereas at the other 

 end of the Humber the reverse is the case. It is therefore 

 reasonable to suppose that the end of the river which contains 

 the most material in suspension is that nearest its place of 

 origin. 



Material in solution is more easily transported than material 

 in suspension ; how then the absence of salt ? 



If the river derived its mud from outside it must have been 

 filled up long since, as the erosion of the coast has always been 

 going on. 



*' Circumstances relative to the Suspension and Deposit of Detritus in 

 the River Humber.' 12 pp. Privately printed, 1903. 



tHig-h water samples. 

 1904 November i. 



