The Birmingham age-herald. [volume] (Birmingham, Ala.) 1902-1950, 1909-10-16
currence of the Inherent materials In each

currence of the different materials in each
of these areas separately.
The crystalline area:
This area, as has already been said,
contains practically every kind of igneous
and metamorphic rock. We will discuss,
however. only the more important of
these. The trap rocks occur in numerous,
long narrow streaks of dykes or sills,
which run in a general northeast-south-
west direction These are found as shown
on the map to occur in the gneisses and
sehists, which cover the larger part Of
this area.
The GRANTEES and syenites occur in much
larger bodies than the traps, and although
their distribution is more or less general
throughout this area, they are more num-
erous toward the southwest portion than
elsewhere. The gneisses and schists, on
the other hand. which cover the bulk of
the area, become more basic in their
nature toward the southeast
The Central of Georgia and the Allan
ia, birmingham and Atlantic railroads
both cut through large number of trap
and granite bodies. In many places quar-
ries could be readily opened
This division OF the state, then, is most
fortunately situated as regards the high
er quality of macadam roads, since much
of the area has both trap and granite, or
naming portions are not far distant from
the first-class macadamizing rocks.
Paleozoic area
In the division of the paleozoic rocks We
find a number of bodybuilding stone
which are of good quality, although none
of them are quite equal to the trap of
| the crystallines. The materials of this
part of the state, which would serve best
! for road-making are: First, cherts of the
Do nj FOR aoff nnf1d
the limestones OF three varieties, (a) the
cambro-silurian (<nox), (b) the Trenton
(Pelham), (c) the sub-carboniferous,
which is represented by the Ft. Payne d.
vision and the mountain limestone. Third,
the sandy shales of the carboniferous. OF
these materials the cherts have received,
and justly so. the widest recognition. The
observation-disclosures or Ft Payne ebert is
the one which has been most extensively
used, since 1t occurs in thick beds and is
as rule, much more easily quarried than
the Knox ebert, though both are of ex-
cellent quality. Both the cherts and the
limestones occur where there is the great
est population. 1t would be more logical,
perhaps, to state this last sentence the
other way, since 1t is the wealth derived
from these formations which has drawn
the population to them. In all the valley
regions of the paleozoic area we have
haustible quantities OF both ebert and
limestone. Since these valleys are the
great passage ways OF our railroads the
haulage of these materials can be reduced
to minimum.
The Sequatchee, Wills. Murphrees, Ca
haba and the Birmingham valley are all
narrow, limestone valleys, with either
one or both sides paralleled by FIT. Payne
ebert ridges. The Coosa valley while
1t is much larger in its extent. has in
places a rather complex structure, so that
the Eft. Payne ebert is brought up in
several ridges accompanied ny the line
stone. So that here also the problem
of road building from these two ma
terials is in general very simple. For
the remaining portion of the Paleozoo
area Included in the coal measures) the
local material best adapted to the con-
struction of roads is probably the sandy
shales, which can be found over larger
part of the area. This application of such
shales, as well as the judicious mixing
of the ever-prescnt clays and sands would
result in much better roads, for this part
of the paleozic Stag. which is one of our
more important road building materials
will be passed over in this discussion ON
account of Its artificial nature and its
we'll known distribution. as will also the
lower grade iron ores, since they usually
occur near the cherts, which are better