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, Gilbeitsville and 

 Mount Upton were regarded as typical localities, the 

 latter affording remains of both animals and plants. 

 Mr. Mather described the " Catskill Mountain series " 

 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 arrangement of the nomenclature of these 

 rocks, the observations of Mr. Mather in Delaware and 

 Ulster counties led to the adoption of the term Catskill 

 sandstone, or Catskill Mountain sandstone, for the whoh, 

 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 Easern 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. 

 Hal] 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 four years 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 

 sructural 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 Cypricardites Calskillensis 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 Anodotita, 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 Holoptychiics. 



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 

 ever 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 

 oi red and greenish marls, brown sandstones and con- 

 glomerates, terminating above by a heavy formation of 

 gray sandstone, the whole lorming the great mass ot the 

 Catskill mountains; and to this formation only should 

 Hi. 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. 



