102 
GELOGY 
most probably re-appear in the marble quarries, distant from twelve to fourteen miles N. W. of Phila- 
delphia, — a range of nearly 300 miles. 
There is a bed of magnetic iron ore, from eight to twelve feet thick, wrought in Franconia, near 
the White Hills, New-Hampshire ; a similar bed in the direction of the stratification, six miles N. E. of 
Philippstown, on the Hudson river; and still following the direction of the stratification, the same ore 
occupies a bed of nearly the same thickness at Ringwood, Mount-Pleasant, and Suckasunny, in New- 
Jersey, losing itself as it approaches the end of the primitive ridge, near Blackwater, — a range of 
nearly 300 miles. 
Instances of the same occur in the transition and secondary rocks ; as the Blue ridge from the 
Hudson river to Dan river, consists of rooks of much the same nature, and included in the same for- 
mation. 
That no volcanic productions have yet been found east of the Mississippi, is not the least of the 
many prominent features of distinction between the geology of this country and that of Europe, and may 
perhaps be the reason why the Wernerian system, so nearly accords with the general structure and 
stratification of this continent. 
It is scarce necessary to observe, that the country must bo considered of tbe nature of the first 
rock that is found in place, even should that rock be covered with thirty or forty feet of sand or gravel, 
on the banks of rivers, or in valleys; for example, the city of Philadelphia stands on primitive rock, 
though at the Centre-square, thirty or forty feet of sand and gravel must be penetrated, before the 
Gneiss rock, which ascertains the formation, is found. 
Beginning at the bay of Penobscot (to the northward and eastward of which most probably the pri- 
mitive descends through a gradual transition to the secondary, and thus into the Independent coal for- 
mation, found in such abundance in Nova Scotia); and proceeding south, the sea coast is primitive to 
Boston, where the transition covers it as far as Rhode-Island. 
ALLUVIAL FORMATION. 
On the south east side of Long-Island the alluvial begins , occupying more than the half of that 
island; its western and northern boundaries are marked by a line passing near Amboy, Trenton, Phi- 
ladelphia, Baltimore, Washington, Fredericksburg, Richmond, and Petersburg in Virginia, a little to the 
westward of Halifax, Smithfield, Aversborough and Parker’s Ford on Pedee river, in North Carolina, west 
of Cambden near Columbia, Augusta on the Savannah river. Rooky Landing on the Oconee river, Fort 
Hawkins on the Oakmulgee river, Hawkinstown on Flint river, and running west, a little southerly, across 
the Chatahouchee, Alabama and Tombigby rivers, it joins the great alluvial bason of the Mississippi a 
little below the Natchez. 
The ocean marks the eastern and southern limits of this extensive alluvial formation, above the 
level of which it rises considerably in the southern States, and falls to near the level of the sea, as it 
approaches the north. 
Tide water in all the rivers from the Mississippi to the Roanoke stops at a distance from thirty to 
one hundred and twenty miles short of the western limits of the alluvial ; from the Appomatox to the 
Delaware, the tide penetrates through the alluvial, and is only stopped by the primitive ridge. 
The Hudson is the only river in the United States where the tide passes through the alluvial, pri- 
mitive, transition, and into the secondary, in all the northern and eastern rivers, the tide runs a small 
distance into the primitive formation. 
Through the whole of this alluvial formation, considerable deposits of shells arc found; and a bank 
of shell limestone beginning in North Carolina, and running parallel to, and within the distance of from 
twenty to thirty miles of the edge of the primitive through South Carolina, Georgia, and part of the 
Mississippi Territory; in some places this bank is soft, with a large proportion of clay, in others, hard, 
with a sufficiency of the calcareous matter to be burned for lime, large fields of the same formation 
