INTRODUCTION. 
85 
The facts which I have here brought together and presented, as I 
believe, in a new combination, and the principles enunciated as the 
results of my investigations upon the phenomena exhibited over a large 
area of country, may, I hope, aid in elucidating certain questions in 
geology, which have hitherto been surrounded with difficulties. After 
the brilliant discussions of the problem of the Appalachian chain by 
the brothers Rogers, and other able geologists, and the masterly eluci¬ 
dation of their beautiful structure, there is certainly little left to be 
done in this regard ; and I cannot hope to offer anything so full of 
interest. At the same time, it does not appear to me that in any of our 
discussions, sufficient importance has been given to the influence of 
this large accumulation of matter along the Appalachian zone; nor to 
the necessary and consequent effect of this accumulation. The depo¬ 
sition along current lines (or shore lines), and the spreading out and 
thinning of the same deposits on receding from this line, is all in 
accordance with the elementary teachings of geology. We know, more¬ 
over, from the nature of the principal limestone formations, and the 
presence of corals and other forms of ancient life in these rocks, that 
they could not have been accumulated in turbid waters, nor along lines 
where argillaceous and siliceous materials were being deposited. An 
entire or almost an entire cessation of these sediments must have taken 
place before calcareous matter could accumulate in large quantities 
along the same zones ; but in these instances, where the amount of 
matter was insufficient, or the force of the current inadequate to trans¬ 
port these materials far beyond the great zone of deposit, there would 
be accumulated in the quiet waters the formations resulting from 
animal exuviae ; and here only could we expect to find coralline lime¬ 
stone and formations of similar character. 
In order, therefore, to have a clear idea of any portion of country, 
it is necessary, in the first place, to take into consideration the mode 
and manner of the original distribution of the sediments constituting 
the series of formations; for on this must depend their ultimate cha¬ 
racter. The slow accumulations in one place, and the rapid accumula¬ 
tion in another place, which we know to be necessary conditions of 
geological deposition, must exert an influence, not alone on the charac¬ 
ter and topography of the country, but upon the nature of its rocks 
and its ultimate productions. 
