MARYLAND GEOLOGICAL SURVEY 69

country, depends for the most part upon its geological constitution, modi-
fied, of course by climate.

It is equally certain that, in connection with climate, the geological
structure and mineral components of any region, determine the character
and the fertility of its soils.

From what is now known of the origin and characters of soils, we must
conclude that the very foundation of any intelligent and practical applica-
tion of science to agriculture in any region, must consist of a thorough
investigation of its geological and mineral constitution.

A survey of this kind for our state should have for its object the deter-
mination of the chemical, physical and other characters of each kind of
rock, bed of clay, sand, marl, or other mineral deposit within our borders.

They should be minutely described, and their position and extent be
accurately shown on a map, and sections upon a large scale. We should
make ourselves acquainted with the properties of every mineral that can
be usefully applied to the soil, and also, with those that may promote indus-
trial operations within our limits. These last should by no means be over-
looked, because of their importance in adding to the demand for the pro-
ducts of the farm.

These views led Mr. Tyson to the preparation of a geological map
" to aid in forming a correct idea of the agricultural and other indus-
trial capabilities of our state. " The base map for the geology was
executed by Mr. August Faul upon data secured from various sources,
chiefly from that of the manuscript map of Mr. J. H. Alexander,
which has been described in a previous chapter.

" The First Report of Philip T. Tyson, State Agricultural Chemist,
to the House of Delegates of Maryland, January, 1860, " contains
several chapters dealing with the general principles of mineralogy
and geology, including a classification of rocks and their geographical
distribution in Maryland. Much attention is given to the limestones
and marls, and their value for agricultural purposes. Much of the
report deals with the soils and the various natural and artificial fer-
tilizers which may be used for their improvement. This report closes
with an appendix in which the mineral resources of Maryland are
briefly described.

" The Second Report of Philip T. Tyson, State Agricultural Chem-
ist, to the House of Delegates of Maryland, January, 1862, " again
dwells upon the importance of geological work in connection with
an agricultural survey. In this second report much more attention is
devoted to the mineral resources of the state, their local occurrences
being more fully described.