and Pennsylvania - Geological Society of America
and Pennsylvania - Geological Society of America
A Stratigraphic Framework for the Catskill Facies,
Southeastern New York and Northeastern Pennsylvania
Frank W. Fletcher, 4 Thompson Court, Reedville, VA, [email protected]
I am profoundly indebted to Jon D. Inners, Robert G.
Sutton, and Donald L. Woodrow for their friendship and
their insights and good counsel regarding Catskill rocks
over the years. “No man is an island, . . .”
THE CATSKILL DELTA
“Any geologist who has followed this series of rocks from
central New York eastward to the Catskills, and then along their
eastern slope into Pennsylvania, knows very well that red beds
appear at different horizons in various parts of the area, and
also realizes the utter impossibility of indicating the same
approximate horizon by drawing a line through the lowest red
beds.” C. S. Prosser, 1894.
JOSEPH BARRELL wrote the first comprehensive
description of the thick wedge of Middle and Upper
Devonian clastic rocks known as the Catskill Delta in
1913. Since that time the stratigraphy, sedimentology,
and paleontology of these rocks have been the
subject of countless publications, including two
notable overviews: Shepps (ed.), 1963, and Woodrow
and Sevon (ed.), 1985. The stratigraphic relations of
the Catskill Delta are well illustrated on correlation
charts published by the geologic surveys of New
York (Rickard, 1975) and Pennsylvania (Berg and
Research Poster Design Services
TIME AND ROCK
► The entire Middle and Upper Devonian sequence
is thickest in eastern New York and thins
► The coarser, non-marine facies, Pocono and
Catskill, predominate in eastern New York, while
the finer-grained, shoreline and marine facies,
Cattaragus, Chemung. Portage, and Genesee,
make up an increasingly greater proportion of the
sequence westward across the state.
► Tongues of black and dark gray shale of the
Genesee facies extend eastward from the Lake
Erie region, first splitting the non-marine Portage
and Chemung facies of central New York and then
the non-marine Catskill facies of eastern New York,
where the are evidence of marine transgression.
►The tongues of black and dark gray shale have
to sub-divide the facies into four
How to orderbeen
groups. Because the anoxic muds that formed
each tongue of black and dark gray shale were
deposited everywhere in the Appalachian foreland
basin at nearly the same time, the shales may be
viewed as time horizons.
Joseph Barrell's paleogeographic map of the Catskill Delta
Representational cross section of Catskill facies east to west across New York state (modified from Isachsen and others, 2000).
The sedimentary sequence of the Catskill Delta
consists six major clastic facies, representing six
discrete environments of deposition associated with
the filling of the Appalachian foreland basin during
the Devonian Period.
Table illustrating the facies of the Catskill delta, together with the
associated rock types and depositional environments.
Isometric diagram of the facies and depositional environments of the
Catskill Delta (modified from Isachsen and others, 2000).
► To trace a single group, such as the Sonyea
Group, from the Catskill Mountains westward to
Lake Erie is to pass from one magnafacies to
another and to cross the Devonian depositional
basin from alluvial fans, to alluvial plain, to
shoreline, to shelf, to slope, to basin floor,
Diagram illustrating the magnafacies concept.
PRESENT AT THE CREATION
During the first Geological Survey of New
York (1836-1843), WILLIAM W. MATHER
employed the name Catskill to denote the red
strata found in the Catskill Mountains.
Together with his colleagues James Hall and
Lardner Vanuxem, Mather assembled one of
the famous rock sequences of the eastern
United States: (in ascending order) Genesee,
Portage, Chemung, and Catskill.
The Search for a Paradigm
paradigm: a set of assumptions, concepts, values and
practices that constitutes a way of viewing reality for the
community that shares them, especially in an intellectual
But in northeastern Pennsylvania, Willard adopted much of
White’s flawed stratigraphic column and terminology and,
like White, pictured the subdivisions of the Catskill as
discrete layers stacked up like pancakes. Willard further
confused the geologic picture by constructing a geologic
map that displays these (fictitious) units as concentric
bands about the Lackawanna syncline.
MULTIPLE WORKING HYPOTHESES
Cats k ill
“Layer-cake” model of the New York Middle and Upper
In Pennsylvania 19th Century geologists also recognized a
“layer-cake” model for the Genesee, Portage, Chemung, and
Catskill sequence; although debates about Portage-Chemung
relationships raged into the 20th Century. I. C. WHITE (1881,
1882) subdivided the Catskill in northeastern
Pennsylvania into eight “members.” White
believed that the boundary between the
Chemung and Catskill occurred at the same
stratigraphic level everywhere in the region, and
that the younger units were stacked up in order
above it. He did not, however, illustrate these
subdivisions on his geologic maps of
and Pike Counties, which displayed only vast
expanses of the “Catskill formation.”
Although revision of Upper Devonian stratigraphy had already begun by the
beginning of the 20th century, not until the 1930's did geologists fully understand that
the Genesee, Portage, Chemung, and Catskill rocks of New York did not lie one above
another in a stacked sequence but were inter-tonguing facies. Chief among the
pioneers of the new paradigm were George H. Chadwick and G. Arthur Cooper in New
York and Bradford Willard in Pennsylvania
CHADWICK proposed a radical division of the Catskill red beds into several
chronostratigraphic units. Although his terminology was later abandoned, he
produced the first geologic map showing individual Catskill formations and their
marine equivalents in southeastern New York. He also drew attention to serious errors
in I. C. White's Catskill stratigraphy, pointing out that it was “scrambled.”
Willard's geologic map of northeastern Pennsylvania
The publication of STATE GEOLOGIC MAPS, in New
York (Fisher and others, 1970) and Pennsylvania (Berg and
others, 1980), brought forth two very different views of the
Catskill sequence. The authors of the Geologic Map of
New York State divided the Catskill facies into five timerock units totaling over 3,500 feet and mapped these
across of broad region of southeastern New York. The
geologists of the Pennsylvania Geologic Survey, however,
illustrated this series of rocks throughout northeastern
Pennsylvania as a single, monochromatic formation.
Geologic map of southeastern New York
(modified from Rogers and others, 1990).
Chadwick's geologic map of southeastern New York
(modified from Chadwick, 1936).
WILLARD (1939) lucidly documented the facies changes of Devonian rocks across
Pennsylvania and the Upper Devonian lithologies involved in the Catskill offlap.
I. C. White's geologic map of Wayne County,
Schematic east-to-west cross section of the Catskill offlap (modified from
Geologic map of northeastern Pennsylvania
(modified from Miles, 2003).
Middle and Upper Devonian Stratigraphy
of the Upper Delaware River Valley
SUBDIVIDING THE CATSKILL FACIES
WALLACE DEWITT, JR. and GEORGE W. COLTON of
the USGS and ROBERT G. SUTTON and his students at The
University of Rochester demonstrated that the black and
dark gray shale tongues split the Portage and Chemung
(marine) facies of south-central New York and form the
basis for the defining the principal rock units (groups)--the
Genesee, Sonyea, and West Falls Groups of the Upper
Devonian Frasnian Stage (see Rickard, 1975). Sutton (1963)
traced dark gray shales of the Rhinestreet Formation
eastward into the Walton Formation of the Catskill facies.
“The key to unraveling the complex facies that occur in this
part of the Devonian has proven to be the tracing of the black
or dark gray shale tongues that persist eastward across the
major facies boundaries.” L.V. Rickard, 1975
A STRATIGRAPHIC FRAMEWORK FOR THE INTERPRETATION OF
CATSKILL SEQUENCES AND PALEOENVIRONMENTS
Employing well data from Rickard (1989), a structure contour
map of the top of the Tully-Gilboa interval, shown below, was
constructed for this study. The map illustrates a broad syncline
underlying a large portion of southeastern New York and plunging
toward the southwest into northeastern Pennsylvania. Further, it
demonstrates that the regional strike of the Upper Devonian strata of
Delaware County (N.Y.) and northern Wayne County (Pa.) is roughly
east to west, fully perpendicular to the strike orientation indicated by
Willard and displayed on his geologic map. Evidently, any structural
influence that the Lackawanna syncline may have on the rocks of the
region is largely local.
Index map to wells
The Frasnian stratigraphic record of south-central New York (modified
from Sutton and McGhee, 1983, after Rickard, 1975).
FRANK W. FLETCHER and DONALD L. WOODROW
(1964, 1970, and 2002) identified dark gray shale tongues
of the Middlesex and Rhinestreet Formations among
Catskill strata in exploratory gas wells and in outcrop at
several localities in northeastern Pennsylvania. WALTER
R. WAGNER (1963) of the Pennsylvania Geologic Survey,
employing lithic and gamma-neutron logs of five gas
wells, traced dark shale horizons in the subsurface
through the Catskill facies of northeastern Pennsylvania.
Dark gray shale tongues, representing members of
the Geneseo, Middlesex, and Rhinestreet Formations,
extend south-eastward from the Upper Devonian
marine facies in Broome County, N. Y. and provide a
basis for extending the Genesee, Sonyea, and West
Falls Groups from south-central New York to eastern
Pike County, Pennsylvania.
Computer-generated, contour map of the top of the Tully-Gilboa
interval in southeastern N. Y. and northeastern Pa. (contours in
The current study of the Catskill
facies in the upper Delaware River valley
utilized subsurface information derived
from a reexamination of lithic
originally described by Fletcher (1964)
and augmented by additional data from
Fletcher and Woodrow (1970) and
Rickard (1975, 1989). The cross section
displayed below demonstrates that more
than 5,000 feet of rock overlie the TullyGilboa in this region. The sequence
includes strata belonging to the
Genesee, Sonyea, and West Falls
Stratigraphic relation of red beds to gamma ray correlation lines within
the Catskill facies of northeastern Pennsylvania (modified from Wagner,
1963). See profile D-E of the index map.
Cross section from Whitney Point (Broome County), N. Y. to Shohola (Pike County), Pa. illustrating the stratigraphic
intervals of the post-Tully (Late Devonian) sequence. Stratigraphic nomenclature for the rocks of the Shohola region is
based on Fletcher and Woodrow, 1970), while the nomenclature of the Whitney Point rocks is after Rickard, 1975.
Stratigraphic column illustrating the Middle and Upper Devonian
units of southeastern New York and northeastern Pennsylvania.
The Lackawaxen Formation represents the westward extension of the Slide Mountain Formation,
which caps the highest peaks of the Catskill
Mountains, and is the non-marine equivalent of the
Rhinestreet shales. The Stockport Formation can be
correlated with the Gardeau Formation, while the
“Damascus” and “Honesdale” intervals are correlatives of the Nunda and Wiscoy Formations.
Berg , T., and others, 1983, Stratigraphic correlation chart of Pennsylvania:
Pennsylvania Geological Survey General Geology Report 75.
Chadwick, G. H., 1936, History and value of the name “Catskill” in Geology:
New York State Museum Bulletin no. 307.
Fisher, D. W., and others, 1970, Geologic map of New York State: New York
State Museum Map and Chart Series No. 15.
Fletcher, F. W., 1963, Regional stratigraphy of Middle and Upper Devonian
non-marine rocks in southeastern New York: p. 25-42, in Shepps, V. C.
---------- 1964, Middle and Upper Devonian stratigraphy of southeastern New
York: unpublished Ph.D. Thesis, The University of Rochester.
Fletcher, F. W., and Woodrow, D. L., 1970, Geology and economic resources of
the Pennsylvania portion of the Milford and Port Jervis 15-minute
quadrangles: Pennsylvania Geological Survey Atlas 223.
Isachsen, Y. W. and others, 2000, Geology of New York: A simplified account
(2nd ed.): New York State Museum Educational Leaflet 28.
Miles, C. E. (compiler), 2003, Geologic shaded-relief map of Pennsylvania:
Pennsylvania Geological Survey.
Prosser, C. S., 1894, The Devonian System of eastern Pennsylvania and New
York: U. S. Geological Survey Bulletin 120.
Rickard, L. V.,1975, Correlation of Devonian rocks of New York State: New
York State Museum Map and Chart Series No. 24.
----------, 1989, Stratigraphy of the subsurface Lower and Middle Devonian of
New York, Pennsylvania, Ohio, and Ontario: New York State Museum Map
and Chart Series No. 39.
Rogers, W. B., and others, 1990. New York State geological highway map:
New York State Museum Educational Leaflet 33.
Shepps, V. C., 1963, Symposium on Middle and Upper Devonian stratigraphy
of Pennsylvania and adjacent states: Pennsylvania Geological Survey
General Geology Report 30.
Sutton, R. G. 1963, Correlation of Upper Devonian strata in south-central New
York: p. 87-102, in Shepps, V. C.
Sutton, R. G., and McGhee, Jr., 1983, The evolution of Frasnian marine
“community-types of south-central Hew York: p. 211-224, in Woodrow, D.
L., and Sevon, W. D.
Wagner, W. R., 1963, Correlation of Susquehanna Group in part of
northeastern Pennsylvania, p. 63-78, in Shepps, V. C.
White, I. C., 1881, The geology of Susquehanna and Wayne Counties:
Pennsylvania Geological Survey Report G 5.
Willard, B., 1939, The Devonian of Pennsylvania: Pennsylvania Geological
Survey Bulletin G 19.
Woodrow, D L., and Fletcher, F. W., 2002, Late Devonian stratigraphy in
northeastern Pennsylvania: in Inners, J. D. and Fleeger, G. M. (eds.), From
Tunkhannock to Starrucca: Guidebook. 67th Annual Field Conference of
Woodrow, D. L., and Sevon, W. D., 1983, The Catskill Delta: Geological
Society of America Special Paper 201.