MARYLAND GEOLOGICAL SURVEY 33

investigated are the building and ornamental stones, lime and cement
products, the clays, the sands, the porcelain materials, the marls, the
iron ores, the coals, the gold deposits, the soapstone, the mineral
paints, the diatomaceous earth (tripoli), the mineral waters and other
miscellaneous products.

BUILDING AND DECORATIVE STONES. —The state of Maryland is
unusually rich in the great variety and excellent quality of its build-
ing and decorative stones. At the same time the central location of the
state, with several prominent cities and towns, which constantly em-
ploy such materials, immediately accessible, renders these products
unusually valuable. The State Geological Survey has already devoted
much attention to the building and decorative stones, believing that a
proper presentation of the subject to the architects, engineers and
consumers of such materials will add very largely to the development
of the industry, not only by inducing larger investments in quarrying
operations, but by increasing the output of those quarries which are
now in existence. The decorative stones, particularly, have been
brought but little to the attention of architects, although they exist
in the state in great variety, many of them equal to the finest foreign
and domestic materials elsewhere obtained. Several important build-
ing-stones, also, have never been used for more than local purposes and
can readily be brought to the attention of outsiders.

LIME AND CEMENT PRODUCTS. —Many of the geological formations
of the Appalachian district of Maryland are characterized by exten-
sive deposits of limestone. Of these the more common varieties are
admirably adapted for burning and afford materials suitable for build-
ing and fertilizing purposes as well as for flux, while the less common
magnesian limestone makes an excellent cement. Although these
products are most abundant in the extreme western portion of the state,
the more highly crystalline limestones and marbles which occur in
many places throughout the Piedmont belt, especially in the northern
tier of counties, can also be burned at times to advantage. Many of
the calcareous clays in the southern and eastern sections of the state
are also well adapted for the manufacture of cement, while some are
sufficiently pure to burn for lime. Relatively little has been done