290 
SCIENCE. 
NOTE UPON THE RELATIONS OF THE ONE- 
ONTA AND MONTROSE SANDSTONES OF 
VANUXEM, AND THEIR RELATION TO THE 
SANDSTONES OF THE CATSKILL MOUN- 
TAINS.* 
By Prof. James Hall. 
Great difficulty has been experienced, from the time of 
the New York Geological Survey, in reconciling the obser- 
vations made upon these sandstones in their various local- 
ities. Mr. Vanuxem indicated the upper formation ot the 
third geological district as the “ Montrose sandstone, or 
sandstone of Oneonta,” and described it as occurring in 
Otsego, Chenango and Broome counties, New York, and 
as covering the whole of the upper part of Susquehanna 
county in Pennsylvania. Oneonta, Gilbertsville and 
Mount Upton were regarded as typical localities, the 
latter affording remains of both animals and plants. 
Mr. Mather described the “ Cat ski 11 Mountain seres” 
as occupying the county of Delaware and the greater 
part of the counties of Sullivan, Ulster, Greene and Scho- 
harie ; but in this description he included the olive slates 
and shales above the Helderberg series, which have since 
been separated as the Hamilton and Chemung groups. 
In the final artangement of the nomenclature of these 
rocks, the observations of Mr. Mather in Delaware and 
Ulster counties led to the adoption of the term Catskdl 
sandstone, or Catskill Mountain sandstone, for the whole, 
including the Oneonta and Montrose sandstones of Van- 
uxem, under the belief that the rocks as exposed in the 
several localities constituted parts of, or different exposure 
of, a single formation. This view has been accepted in 
all subsequently published observations, and universally 
believed to be the true one. 
My first observations in this part of the country, 
previously to 1870, were made in 1844, but at that time 
only for the collection of fossils. In 1863 I made a 
section across the formations from Schoharie to Oneonta 
and thence to Franklin and to the South-westward of 
that town, and across the country to Delhi in Delaware 
county, returning to Schoharie by a more Eas'ern route. 
The results proved unsatisfactory from the fact that 
crossing from Oneonta and approaching Franklin over 
red and mottled shales and sandstones with an appar- 
ently southwest dip, these were succeeded by gray and 
greenish shales and sandstones carrying Chemung fossils ; 
and again, on the road to Delhi, these latter were suc- 
ceeded by red rocks. 
Although, in the mean time having visited Montrose 
and some other localities of these sandstones, it was not 
until 1869 and 1870 that I was able to give any 
special attention to the relations of these formations on 
the Western slope of the Catskills, in the towns of One- 
onta, Guilford, Sidney Plains and the adjacent country, 
still finding myself quite unable to parallelize the forma- 
tions as there existing, with the sandstone of the Catskills. 
In the latter year Mr. George B. Simpson and Dr. J. W. 
Hall were employed in this region, and directed to make 
cross sections of the country in different directions ; and 
their observations, after having reviewed the principal 
localities in company with myself, gave the same re- 
sult, viz. : that the extensive formation of red and green- 
ish mottled shaly sandstones, with brownish red and gray 
diagonally laminated sandstone, in the localities of One- 
onta and Mount Upton and other places in the same 
region, were succeeded by sandstones and arenaceous 
and argillaceous shales, carrying great numbers of marine 
fossils known as belonging to the Chemung group, to- 
gether with some bones and teeth of fishes of a peculiar 
character. To the latter again succeeded red and green- 
ish gray or brownish gray beds, which in one locality in 
* Read before the National Academy of Sciences, N. Y., 1880. 
the town of Andes had already furnished scales of 
Holoptychius, and a nearly entire specimen of that fossil 
fish. 
Notwithstanding the clearly ascertained order of suc- 
cession among the members of the higher formations of 
the State, I have hesitated to publish results in opposition 
to the conclusions of my former colleagues, believing 
that I might possibly have been mistaken in my interpre- 
tations of the geological structure of the country. 
About the same time, I employed Mr. Andrew Sher- 
wood to work out the geological structure of the Catskill 
mountain region, and in 1875, after fouryears of investi- 
gation, I was able to present to the American Association 
for the Advancement of Science, and subsequently to the 
Academy, a large geological map, showing the general 
s ructural features of the Catskill region. In this 
work upon the structural character, in regard to the 
anticlinal and synclinal arrangement of the strata, the 
question of a subdivision of the formation has not been 
presented ; and it was only in the present year, 1880, that 
Mr. Sherwood was again employed; to complete investi- 
gation for a final geological map. In this work it became 
necessary to review the section along the Schoharie 
creek, which had previously been left at the commence- 
ment of the red rocks ; and also of the country about 
Oneonta, Mount Upton, Guilford, Sidney Plains and 
Franklin. 
The result of these observations has been entirely con- 
firmatory of the results brought out by Messrs. Simpson 
and Hall in 1870. In accordance with our present knowl- 
edge therefore, we are compelled to adopt the view that 
the red and gray rocks of Oneonta and Mount Upton, 
beginning at the latter locality, with shaly beds contain- 
ing large numbers of a single fossil species described by 
Mr. Vanuxem as Cypricardiles Catskillensis and C. Au- 
gusta, and supposed to be the equivalent and actual con- 
tinuation of the Catskill red sandstone of Delaware 
county, are in fact succeeded by rocks carrying large 
numbers of Chemung fossils. 
The fossil shell described by Mr. Vanuxem has the 
form and character of an Anodofita, and is apparently 
a fresh water form, and occurs in association with large 
numbers of fragmen'ary and drifted land plants. The 
formation consists of red marls, red and gray sandstones 
in alternating bands, the whole diagonally stratified, and 
attaining, in this region, a thickness of at least 500 feet. 
The fossiliferous beds of the Chemung are found lying 
upon that formation between Norwich and Oneonta, and 
to the east of Sidney plains, and at or near Franklin, 
where they apparently pass beneath the great red sand- 
stone formation of the Catskills, which is characterized 
by the presence of bones and scales of Holoptychius. 
From all these facts it would appear, that some time 
after the Hamilton period, the open sea was cut off from 
this area during a long period, that dry land producing 
abundant vegetation with estuary and fresh water condi- 
tions ensued ; and that at a later period the subsidence 
of the coast allowed the influx of the ocean which spread 
over the area westward, giving beds of shale, sandstone, 
etc., charged with marine fossils of the Chemung period. 
That again, the open sea was invaded by an elevation of 
the littoral line, and then followed the great accumulation 
of red and greenish marls, brown sandstones and con- 
glomerates, terminating above by a heavy formation of 
gray sandstone, the whole forming the great mass ot the 
Catskill mountains; and to this formation only should 
the name of Catskill sandstone be properly applied. 
This conclusion, which is sustained by our present 
knowledge, suggests some very important considerations 
concerning the relations of the Hamilton, Portage and 
Chemung groups, which will be discussed at some future 
time, and which, when investigated under the present 
phase of our knowledge, may solve some existing prob- 
lems regarding these formations. 
