30 L. Lesquereux on the Coal Formations of North America. 
eoal-felds were united in one area, their surface would fairly b be 
estimated at 300,000 nee miles. Now, in the new theory pre- 
sented above, we find it asserted: that the shales and the sand- 
stone of the coal have been deposited upon the surface of the 
peat bogs of the coal formations by the inundations of some large 
river! Would it be possible for a sound mind to admit that a 
river can cover at once or even by repeated inundations, a surface 
of three hundred thousand square miles with a deposit of sand 
from six to one hong feet thick, which is the thickness of 
the Mahoning sandston 
Giving to the herdothindie the widest range of probability and 
considering as a peculiar Delta the area (sixty thousand miles) of 
the Appalachian coal-fields, still we find no geological phenomena 
of our time to justify it. Let us compare a few data. The whole 
lain of the Mississippi, comprising the Delta, from Cape Girar- 
Per 50 miles above the junction of the Ohio to the sea, covers 
an area of about 30,000 square miles. Would it be possible to 
sup that an inundation would ever cover this whole surface 
with only a few feet of sand or of mud? According to the ob 
servations mentioned by Forshey, the mud transported in one 
year by the Mississippi river would cover a surface of twelve 
square miles with one foot of alluvium. At this rate it would 
take five thousand years for a river as mighty as the Mississippi 
to cover a single bed of the Appalachian coal-fields with one foot 
of shales. 
Moreover, it is well known that a river cannot spread any of 
= transported material in a uniform manner, especially not in 
e deltas which are exposed to: continual changes. For a delta 
is never composed of compact materials. It is mostly cut by 
variable and sometimes under currents covered only by a crust — 
vegetation, sustained by drift wood or floating upon the deep 
and muddy waters. These currents cause constant alterations: | 
extensive marshes sink and are buried to-a great depth below a : 
ge eneral level of the country; lakes appear in some places am 
ry up in others; some bayous. are filled and others opened. — 
ahere are few square miles around New Orleans and on the — 
