208 PHYSIOGRAPHY, GEOLOGY AND MINERAL RESOURCES
among them the Capitol, Patent Office, old Post Office and Congres-
sional Library buildings in Washington, the Baltimore and Ohio
Central and the Fidelity and Trust Deposit buildings in Baltimore, as
well as other public and private structures..
The rock quarried near Ellicott City on the Baltimore county side
of the Patapsco river is a fine-grained gray granite with a decidedly
foliated or gneissic structure. On the opposite side of the river in
Ellicott City itself the rock is more massive and also has a porphy-
ritic structure, large flesh-colored crystals of feldspar being more or
less regularly developed through it. The most perfect variety of
this granite porphyry presents a striking and beautiful appearance.
This rock was worked at an early date and afforded much of the
material out of which the Cathedral in Baltimore was constructed.
Many other structures have been built of the same rock in more
The granite found at Guilford, in Howard county, is of excellent
quality and has a somewhat finer grain and lighter color than that
occurring near Woodstock, but as yet has not been as extensively
worked. There are also quarries at Sykesville, Garrett Park, Gun-
powder, Texas, Relay and Dorsey's Run, all of which are susceptible
of more extensive development.
The more solid varieties of the gneiss occurring in and near the
city of Baltimore are extensively quarried for building and founda-
tion stone. This rock is of a dark gray color and occurs in parallel
layers, which are more or less contrasted. Buildings constructed of
this stone, of which there are many in Baltimore, present an agree-
able effect. The oldest and most important of the gneiss quarries
are those on the eastern side of Jones' Falls, opposite Druid Hill Park.
Openings of the same rock have also been made at Gwynn's Falls,
Edmondson Avenue, near McDonogh, and at other places. The
great gneiss quarries at Jones' Falls were in active operation very
early in the century, the earliest openings being situated on the
western side of the creek.
The total value of the output of granite and gneiss in Maryland in
1896 was $355, 000.