MINERAL GEOGRAPHY 123 
States, across the lower waters of the St. Lawrence, into Labra- 
dor, and is covered by No. 5 through a distance of ahout thirty 
miles, north of Trenton, in New Jersey, so as to form at the sur- 
face two separate bodies of rock. 2. West of this is a transition 
formation, commencing in Canada, occupying the western part of 
Vermont, embracing as it advances towards the south-west, the 
larger part of the Alleghany mountains, but not extending much 
beyond them, and containing in Pennsylvania immense beds of 
anthracite coal. 3. Farther west still, are the secondary strata of 
the valley of the Mississippi, through which the primitive Ozark 
mountains protrude, in the states of Arkansas and Missouri. 4. 
The tertiary distinct on the sea board. 5. The body of sandstone 
and trap, commencing in New Hampshire, and extending with in- 
terruptions into South Carolina. The richest metalliferous dis- 
trict within the territory of the United States, is in the Territory 
of Wisconsin, and the states of Iowa, Illinois, and Missouri, in all 
of which are immense quantities of lead ore, imbedded in an an- 
cient secondary limestone. The iron Mountain in Missouri, 300 
feet high, and two miles in circumference, is a mass of the secu- 
lar oxide of iron. 
GEOLOGY OF NORTH CAROLINA. 
61. Tertiary Strata. An obvious and striking feature in the 
geology of North Carolina, is, the division of the state by a line 
running in a north-easterly and south-westerly direction, into two 
parts, of nearly equal extent, but, differing widely from each other, 
in composition, structure, soil, and vegetation. One is a region of 
fixed rocks, without organic remains, and covered its natural state, 
with forests of oak, hickory, and other trees, having deciduous 
leaves ; the other made up of beds of clay and sand, with immense 
quantities of shells imbedded in them, and the favorite habitat of 
the long leaved pine. From the first settlement of the country, 
till within a few years, the received opinion has been, that the 
low-country as well of North Carolina as of the other Atlantic 
states, has been gradually thrown up by the waves, and gained from 
the sea. This view of its origin is proved to be untenable by dif- 
ferent facts and agreements. 
1. By its elevation above the bed of the ocean. The surveys 
that were instituted with reference to the construction of the Wil- 
mington rail road, show an elevation of the general surface of 
Duplin Count)'-, of between one hundred, and two hundred feet, 
above the height of mean tide at Wilmington. But Duplin is one 
of the lower counties. The court, house is not more than 35 
miles in a direct line from the sea, whilst it is upwards of 60 
miles from the upper limit of the sand ; and throughout the latter 
distance, the ground constantly rises, as is proved by the fall of 
the streams, which is also more rapid and considerable, as we ap- 
proach their sources. The general elevation of the upper border 
