STRATIGRAPHIC GEOLOGY 341 
portion of the United States was written by Dr. Samuel L. Mitchill 
of New York concerning the rocks of that state and published in 
the Medical Repository in 1798 and 1799. At the close of the 
eighteenth century scarcely half a dozen men in this country under- 
stood the elements of geology. One of these was Professor Ben- 
jamin Silliman, who oraduated at Yale College in 1796, and in 
1818 founded the American Journal of Science, which was the first 
distinctly scientific periodical published on this continent that has 
continued to the present time. An idea of the equipment for the 
study of this science in the leading scientific educational institu- 
tions of this country at the beginning of the nineteenth century may 
be gained from the statement that “Professor Silliman carried the 
whole mineral collection “at Yale for examination and study to 
Philadelphia, in a candle box.” 
Prominent among these early students of geology were William 
Maclure, who published the first geological map of the United 
States in 1809, and Amos Eaton, a eraduate of Wilhams College, 
who later attended lectures in Yale College and in 1817 became 
a lecturer on chemistry, botany, mineralogy and geology in his 
alma mater. Eaton and Theodore R. Beck were selected by the 
wealthy Patroon the Hon. Stephen Van Rensselaer, in 1820, to 
conduct the first geological survey of any district in this country, 
viz: Albany county, New York. Two years later he was appointed 
to survey that portion of New York state adjacent to the Erie 
Canal, which was then in process of construction. The expense 
of this pioneer work was borne by Van Rensselaer, this country’s 
first patron of the science. Eaton classified the rocks to a certain 
extent and to one of the divisions he gave the name of Corniferous 
limestone, a name that for many years has been well known in 
this state. Later Van Rensselaer made Eaton senior professor in 
Rensselaer school in the city of Troy, now known as the Rensselaer 
Polytechnic Institute, which became under his instruction for a 
time the most noted school in geology in this country. 
To the west of Albany county les the rugged one of Schoharie, 
crossed by the northern escarpment of the Helderberg plateau, or 
mountains, and deeply trenched by the Schoharie cree k, a southern 
tributary of the Mohawk river. In the Schoharie valley near the 
village of that name lived the Gebhards, a prominent and well-to-do 
family of gentlemen farmers, father and son, who between 1820 
and 1835 worked out the succession of Silurian and Devonian 
1 The statement of Professor Chester Dewey is that ‘‘The Society for 
Promoting Agriculture, Arts and Manutactures,”’ incorporated in 1795, after- 
wards merged iu the Albany Institute, appointed Dr. Mitchill Commissioner 
to examine and report on the ‘Minerals of the State;” but his report treated 
chiefly of the rocks. (Tenth An. Rept. Regents of the University of the 
State of New York, 1857, p. 14, f, n.) 
2 Aloyiales, jo, WEE 
