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granitic debris has flowed, and met the river water in uproar- 
ious contention, would consequently agitate the very bottom 
at every ebb and flow of its tide, by which some change in the 
currents of the oceanic deposited debris of the rivers might 
begin to form a sandbank at the very junction ; and where these 
forces were equal, or their powers exhausted, this sand- 
bank or bar would have a tendency to check the force of both. 
We have seen similar effects in the change of currents in the 
drifting of snow. The continual accumulation would shut 
out the ocean, and convert the river waters into a sluggish 
estuary ; and all future deposits would be supplied from the 
river or rivers through the varied deposits of more than 
600 yards of strata, alternating with sandstone, shale, coal, 
and ironstone, &c. Just in proportion to the gain of the 
sandbank on the river's current, would be the dry land or the 
estuary covered with water. I think this is sufficient to account 
for the varied strata without the hypothesis of an alternate 
earthquake, or volcanic upheaval and submergence. There is 
no need of an upheaval to cause dry land, as the silt deposited 
from the rivers would raise the delta, and a little addition to 
the sandbank or slight submergence would put the delta 
under water again. I have a great objection to multiply 
causes in nature when we have daily before us adequate 
phenomena. It has been customary to account for the coal 
strata by upheavals and depressions, but there is no evidence 
of violence from the deposit of the sandstone grit until the 
last member of the coal series was finished. The only 
evidence of upheaval is at the Permian period, when the 
backbone of England, as it is sometimes termed, was raised. 
No doubt it was at this period when our coal series was so 
disrupted. There is no appearance of any erupted matter in 
the Yorkshire Coal Field ; but there are trap dykes in the 
Northumberland and Durham series. I have no wish to go 
into the salt or freshwater origin of the intermediate shales, 
