TRANSITION AND SLATfc ROCKS. 135 
crust of the globe, of the four earths, silica, alumina, lime 
and magnesia ; but the quantity of lime entering into it is small. 
The most common and abundant constituent, is a compound of 
silica and alumina; simple argillite, or clay slate. This prevails 
especially near its two extremities ; in Granville, Person, Anson, 
Mecklenburg and Stanley. In these we find argillite almost to 
the exclusion of every other mineral. The slate undergoes de- 
composition very slowly, and has to this clay covered itself with 
a thin coating only, of earth. It furnishes therefore the most 
decisive evidence of the manner in which the soil of the whole 
upper country has been formed. When an attempt is made to 
dig a well, the work advances rapidly at first, but at the depth 
of three or four feet, and frequently much sooner, a slaty struc- 
ture begins to develope itself in the earth that is thrown out, the 
spade is exchanged for a mattock, and long before water is reach- 
ed, the excavation has to be carried on in a mass of rock, requir- 
ing the constant use of gunpowder to shiver it to pieces. Rain 
water will of course penetrate with difficulty, and in small quan- 
tities, into a country so constituted ; the larger part of that which 
falls, will pass off immediately into the creeks and rivers, springs 
will neither be numerous nor copious, and in a season of long 
drought, the slate country suffers more severely than any other. 
The soil is never fertile, though in a summer when rain falls fre- 
quently, tolerable crops are obtained. 
In the counties of Montgomery, and Stanley, (and the separa- 
tion of the original county of Montgomery into these two, may 
be numbered among the grossest follies of recent legislation,) but 
especially in the former, the simple and pure argillite gives place 
to a triple compound of silica, alumina, and magnesia, of which, 
a range of rugged, but not high nor fertile mountains, passing 
through the centre of the county, and amongst, and partly on 
which Lawrenceville stands, are composed. The clay slate ap- 
pears to occupy a lower level, and to be found especially around 
the bases of the highlands, as on Clarke's creek, and the Uwhare 
in Montgomery. In other places both the alumina and magne- 
sia disappear, and we have beds of hornstone, flinty slate, and 
jasper, such as those crossing the Yadkin at the Narrows, and 
Great Falls, over which the water has poured for ages, and may 
continue to pour for ages to come, without producing any other 
effect than that of giving an imperfect polish to their surfaces. 
Intermingled with all these, and interstratified with them, are 
other beds, sometimes massive, and sometimes exhibiting like the 
rest a slaty structure, constituted of water-worn, siliceous, and 
other pebbles, united by a cement of silica, forming a rock of 
great solidity, proving that this formation is not co-eval with the 
existence of the earth, but made up of the fragments and ruins of 
older rocks. These conglomerates contain particles of gold im- 
bedded along with the pebbles. The Beaver Dam and Parker's 
surface mines, are amongst rocks of this character, so also is Reid's 
