The Providence news. (Providence [R.I.]) 1891-1906, 1895-05-17

served, in nearly all parts of the State,
rocks and boulders, lying in many cases
by the roadside, which, IL broken by a
portable steam crusher and rolled, would
make excellent and economical roads.
DEPARTMENT OF THE INTERIOR,
UNITED STATES GEOLOGICAL SURVEY,
WAsHINGToN, ID. g., Dec 10, 1893.
Mr.. Charles +. Chase. Secretary, 65 Westmins-
ter street, lrovidence, r. /.
DEAR SIR--I beg to acknowledge the
receipt Of your communication of the 10th
inst, requesting, for the use of the road
committee OF the State Legislature, a brief
description of the rocks of the State with
reference TO their utility as road mate
risls, and in reply thereto submit the
following observations:
The State az whole is not we'll pro-
vided with natural road materials. 1t,
however, contains some rocks which are
commendable for such use. OF these the
best, which is indeed probably among
best sources OF road metal in New En-
gland, is the magnetic iron ore of the
Iron Hill in Cumberland. This rock is,
on account OF the titanium which it con-
tains, untitled for use in the manufacture
OF iron, but because OF its hardness and
toughness will make an admirable mate
rial for the construction OF highways after
being crushed. AS yet this material has not
beensried, but there seems TO be no doubt
that 1t will serve extremely well in road
building. Next after this, Iron Hill
magnetic may be reckoned the granitic
rocks which are we'll developed at various
points in the State, especially in the
district about Westerly. Some of this
Anca arfY nrl.
rolled will make a fair roadway, less en-
during that is desirab BILE TO the trend of
the wheels, but suited for light travel.
At various points on the western border
of the State there are considerable depos-
its OF trap rock belonging in the group
known to photographers as Hyperite.
This once molten rock contains a large
amount of Iron and hornblende. am
not aware that it has been used on roads,
bat is promising material for such SER
vice.
The hornblende schists, which are con-
siderably developed near Pswtucket, may
perhaps be used to advantage in crushers.
They are, however, rather soft for ex-
tended use. The quartz porphyries near
Diamond Hill, though affording rather
brittle stone, a material which does not
however, be sdvantsgeously used in the
region near the locality, or at points
readily accessible by railway. The quartz
OF Diamond Hill make fair road. 1t
does, however, grind to powder, but it
compacts fairly well under the tread
OF wheels or where tho pressure
is applied by the roller. Between the
granitic deposits and the newer rocks,
mostly Of the csrboniferous age, there
are frequently accumulations formed in
the coal measures that have often been
broken up to crystalline bits. In general,
these rocks, which are termed by geolo-
gists "arkose," are rather soft, but on he
northwest side of Dumplings, on
Conanicut Island, they afford q firm
material which is likely to prove service
able for use on roads. The softer varieties
OF arkose often merge into and are hard to
separate from crystalline rocks which have
decayed in places, such as are
found in Scituate, where the de-
cay has softened the material to the
point where it can be readily removed by
the pick and shovel. Materials of the
above description make very fair roads.
They are likely to soften on the surface
in the spring season, but they uphold the
wheels in fair manner.
In the greater part of New England,
the trap rocks afford the best materials
fer road Masking. Rocks OF this descrip-
tion appear to be uncommon in Rhode
Island. As yet the geological study of its
area is not sufficiently advanced to afford
full information concerning the localities
where trappean rocks occur.
The pudding stones or conglomerates,
which plentifully occur in the carboni-
ferrous basin of eastern Rhode Island,
afford in general very fair material for use
on roads when broken by steam crushers.
Where the pebbles OF conglomerate are
very small it is, however, necessary to
crush the mass to undesirable fineness
lest smooth stones be built into the road
way.
The glacial drift OF Rhode Island does
not in general afford coed road materials.
Where, however, the beds are reasonably
free OF clay and contain numerous bould-
ers and large pebbles, these may often be
advantageously broken in the crusher
and used as "road metal" In general,
however, these superficial deposits are
less favorable for this use than those in
other parts Of New England.
The only way properly to set forth the
road material of Rhode Island is to have
a survey OF the under geology made, as il
can be done, in rapid manner, with
special reference TO the material useful in
road construction, the value Of su distances
being determined by tests such as may be
applied in the laboratory in the manner
In which they have been turned to ac-
count by French road engineers. / am.
with respect,
Il