with a series of rocks which, up to that time, had received no full elucidation in any country; hence the necessity of comparing observations and views, with the purpose of agreeing upon some common terms of designation became apparent, and very soon, imperative. The comparison of observations and interchange of views led to the opening of correspondence, by a formal resolution of the New York Board, with other geologists, especially with those engaged in State surveys, of which several were then in progress. This correspondence led to an agreement for a meeting of geologists in Philadelphia in the spring of 1840, and this assemblage of less than a score of persons led to the organization of the American Association of Geologists, which, at a later period, on the occasion of its third meeting, added the term Naturalists; and finally, by expanding its title, it became the American Association for the Advancement of Science. It is due to the State of New York that these facts appear in this connection, and it is but fair to state that her geologists have contributed largely to the subjects of discussion and to the array of new facts which have been brought before the scientific world through the agency of this organization.
During the few years of field work, the New York geologists had harmonized the conflicting views before entertained regarding the relations of the geology of the eastern and western parts of the State; they had traced the boundaries of the successive geological formations; had shown the extent and limits of the iron-bearing strata, and had rectified the erroneous views which had been held till some time after the commencement of the survey, regarding the boundaries and distribution of the salt-bearing formation of the State. They had, also, shown the limits of the granitic formations, and their associated mineral products; the thickness and extent of all the limestone, sandstone, and shale formations of the State, and had definitely settled the relations of the rocks of New York to the coal-measures of Pennsylvania and the geological formations of the Western States.
Their labors had in a great degree quieted the feverish anxiety regarding the discovery of coal within the limits of New York, for which frequent explorations had been made in the black slates of the Hudson River Valley and elsewhere, involving the expenditure of much money and loss of time. A rational idea of the general geological structure, and the relations of the geological formations of the State, had been acquired by the intelligent population, through the annual reports of the survey, which presented the results of each season's work in the field.
- Professor Mather has estimated, from what he regarded as reliable data, that the fruitless coal-mining enterprises which had been undertaken in the Hudson Valley alone, during the fifty years preceding 1840, had cost more than a quarter of a million of dollars. The sums thus expended in other parts of the State, though doubtless much less, must, nevertheless, have been very large.