Map of 18 Mile Creek near its mouth at Lake Erie. Eden NY 7.5 minute quadrangle, 1949. The large blue
numerals indicate the sections designated by Grabau. Scale is in km.
18 Mile Creek, near Highland and North Evans, Erie Co., NY
Eighteen (18) Mile Creek in Erie County is one of the best known exposures of the Ludlowville and Moscow Formations in Western New York. This locale, and the adjacent cliffs on Lake Erie, were the subject of two monographs by Amadeus Grabau (1898, 1899), and numerous subsequent studies to the present day. The Ludlowville and Moscow strata are exposed at the lower end of the creek, from its mouth at Lake Erie (a short distance north of Highland, NY) to North Evans, NY. The Creek at the stretch forms the boundary between the Towns of Evans (on the southwest bank) and Hamburg (on the northeast). The locality is most accessible by foot from Old Lake Shore Road where it crosses the creek, not far from its mouth. It should, however, be noted that there is no roadside parking permitted at this point. Grabau divided the exposures in the creek gorge into 8 sections, shown in the map below.
Map of 18 Mile Creek near its mouth at Lake Erie. Eden NY 7.5 minute
quadrangle, 1949. The large blue
numerals indicate the sections designated by Grabau. Scale is in km.
Section 8
The section of 18 Mile
Creek between its mouth at Lake Erie and the Old Lake Shore Road bridge was called Section
8 by Grabau. The Wanakah Member of the Ludlowville Formation is exposed in the cliff
on the southeastern bank of the creek (the Evans side). However, accessibility is
difficult at high water, and the land generally posted.
Grabau's Section 8, 18 Mile Creek. View from the Old Lake Shore Road
bridge looking downstream (Nov. 1999)
Section 7
Grabau's
Section 7 stretches from the Old Lake Shore Road bridge to the NY Route 5 bridge, and is
the most readily accessible. In this section the northeast wall of the gorge
(Hamburg side) has excellent exposures of the upper part of the Wanakah Shale (most of the
lower levels are covered by talus), as well as the Tichenor Limestone and Windom Shale
members of the Moscow Formation. All are accessible by climbing the talus slopes,
while specimens may also be found in the talus and in fallen blocks of the Tichenor LS.
18 Mike Creek, Section 7, looking upstream from the Old Lake Shore
Road bridge, November, 1999.
The Tichenor Limestone forms a prominent protruding band half-way up the cliff in Section 7. The Tichenor is called the "Encrinal Limestone" by Grabau, due to the profusion of crinoid fragments in this layer. This member of the Moscow formation is approximately 30 to 37 cm thick in Section 7, consisting of two layers (KAW, personal observations). The upper, courser grained layer is ~20-25 cm thick, while the lower layer is 11 to 12 cm thick. The distinction between the two layers is often quite prominent, especially on well weathered surfaces. The upper layer is more resistant, and weathers with a relatively smooth dark-gray to brown surface. The lower layer weathers more quickly, with an uneven pitted surface and a lighter color than the upper layer. However, the distinction between the two parts sometimes disappears, especially in the middle of the section. Large "heads" of the tabulate coral Favosites are occasionally seen in cross-section in the lower part of the Tichenor Ls in Section 7. Some of these contain petroleum filling the "cells" of the coral colony. Pyrite is also a common constituent of the Tichenor. Its oxidation leads to rusty brown staining of the weathered surfaces of the limestone band, especially, but not limited to, the lower portion. The Tichenor Ls is richly fossiliferous, but fossils are difficult to extract. Collecting is most easily done on fallen blocks at the base of the talus slopes near the creek's edge. The weathered surfaces occasionally yield excellent specimens, especially of bryozoa. This author has observed 56 different species in the Tichenor Ls at Section 7 and the nearby Lake Erie cliffs.
The top-most 2 meters of the Wanakah Shale is the most fossiliferous portion of the member exposed in Section 7, both in terms of number of species and number of individuals. This upper portion of the Wanakah Member is now termed the "Blasdell Bed" (Kloc, 1983). Originally, Grabau designated the contained prominent fossil horizons by their dominant fauna components. The uppermost fossiliferous bed (approximately 10 cm below the Tichenor Ls) was called the "Stictopora Bed" due to the abundance of the branching bryozoan Sulcoretipora incisurata (originally called Stictopora). Below this is the highly fossiliferous "Demissa Bed", located approximately 33 cm beneath the Tichenor Ls. This bed contains the brachiopod Strophodonta demissa, as well as many other brachiopods (including the large Spinocyrtia granulosa), bryozoa, pelecypods, gastropods, trilobites, crinoids, etc. The "Athyris spiriferoides Bed" of Grabau is located approximately 2.75 meters below the Tichenor Ls. This horizon, marked by a layer of concretions, contains the brachiopod Athyris spiriferoides, often with the two valves still articulated, and often bearing numerous species of epizoites. At present this bed is largely covered with talus, but is occasionally accessible. A micro-stratigraphic column of the Upper Wanakah Shale, including the distribution of different faunal groups, can be accessed here: Wanakah Shale Microstratigraphic Column.
Section 7, 18 Mike Creek, looking upstream from the Old Lake Shore
Road bridge- a closer view of the cliffs in the middle of the section. The Tichenor
Ls forms a persistent band a short distance above the talus, and is also found as fallen
blocks at the creek edge. The Genundewa Ls forms another protruding band a short
distance from the top of the cliff. Photograph taken approximately 1970.
Section 7, 18 Mile Creek, view downstream from the NY Rt. 5 bridge,
November 1999. For reference, the indentation in the cliff, below the white house
above, is the same as that seen in the extreme right edge of the1970 picture
above. The indentation has been cut by a small intermittent stream falling into the
gorge at this point.
Two thin shale layers, the Genesee Shale and the Penn Yan Shale, and the Genundewa Limestone (all of the Genesee Formation) are also observable near the top of the cliff, but are inaccessible for collecting at this section (except for fallen blocks). The Tichenor and Genundewa Limestones are much more resistant to weathering than the shales, and form two prominent protruding bands in the cliff that serve as excellent marker strata.
Section 5
The northeastern bank of 18 Mile Creek
upstream from the NY Rt. 5 bridge was called Section 5 by Grabau. In this section
the Tichenor Ls forms a sidewalk-like walkway at the base of the cliff, and a small falls
in the creek near the upper end of this section. The uppermost (and arguably the
most fossiliferous) portion of the Wanakah Shale is exposed in the creekbed at the lower
end of this section, and is accessible at low water (or with wading).
The Windom Shale is especially well exposed for collecting here. The lowest 2 feet (60 cm) of the Windom are the most fossiliferous here. At the very base of the Windom is the Ambocoelia Bed, containing innumerable individuals of the small brachiopod Ambocoelia umbonata. Above this is the Spinatrypa/Coral Layer, also known as the BayView Coral Bed . This layer contains the brachiopods Spinatrypa spinosa and Pseudoatrypa devoniana, and the large rugose corals Heliophyllum halli, Cystiphylloides americanum, and C. conifollis. Above the Spinatrypa/Coral Layer is the more calcareous Smoke Creek Trilobite Bed. The brachiopods Mucrospirifer consobrinus and Rhipidomella vanuxemi are prominent here, as well as the small rugose corals Stereolasma rectum and Amplexiphyllum hamiltoniae. This layer also contains many individuals of the trilobite Phacops rana, generally as molts consisting of separated cephalon, thorax + pygidium, etc., although complete individuals are occasionally found.
(Left) Section 5, 18 Mile Creek, looking downstream from
approximately the middle of the section. (Right) View of the section looking
upstream from the lower end of the section. The Tichenor Ls forms the
"sidewalk" in this section. Most of the exposed cliff in these
views is the Windom Shale. The Genundewa Ls. is largely hidden by the vegetation at
the top of the cliff. (Photos July 1997)
Section 1
Grabau’s
Section 1of 18 Mile Creek is the most upstream section he described. It is approximately
2.2 km (as the crow flies) from the Lake Erie shore, and approximately 1. 1 km from the
hamlet of North Evans. Section 1 runs from the railroad (Conrail) bridge crossing the
creek at the upstream end to a small lateral ravine extending northeast from the main
gorge at the lower end.
Section 1, 18 Mile Creek, looking upstream from the south bank
towar the Conrail railroad bridge over the creek. When this picture was taken (July 1996)
the water level in the creek was high, and the Genundewa LS is just under water on the
north bank.
The lowest stratum exposed is the top of the Windom Shale of the Moscow Formation of the Hamilton Group (i.e. Middle Devonian) in the stream bead and base of the cliff. The remainder of the exposed rock is Upper Devonian of the Genesee, Sonyea, and West Falls Formations of the Seneca Group. From the top of the exposure, the units are:
The Leicester Pyrite, which unconformably overlies the Windom Shale in other parts of Western New York is absent in Section 1 of 18 Mile Creek, Similarly, the Penn Yan and Genesee Shales (of the Genesee Formation) are absent, or are represented by thin shale layers separating the North Evans Ls from the Genundewa Ls or beneath the North Evans, above the Windom Shale.
Section 1, view of the north bank near the center of the section
(July 1996), with blocks of the Genundewa Ls
emergent at the waterline in the creek.
Of particular interest in Section 1 are the Genundewa and North Evans Limestones. The Genundewa Ls, called the "Styliolina Limestone" by Grabau, is comprized chiefly of the small conical shells of the cricoconarid Styliolina fissurella Hall. Some plant remains (branches or logs) are also present, as well as conodonts and occasional fish armor plates. The Genundewa varies from 4 to 8 inches in thickness (10 to 20 cm).
Underlying the Genundewa Ls is the North Evans Ls. This unit was termed the "Conodont Bed" by Grabau, who treats it as a part of the Genundewa Ls. The North Evans varies greatly in thickness, reaching a maximum of 10 to 13 cm in Section 1. Its contact with the Genundewa Ls also varies. At places it they are separated by a thin shale layer, while elsewhere they are in direct contact. The North Evans Ls is a coarse grained Ls made up of crinoid fragments, quartz sand, small pebbles, etc., suggesting that it is a sandbar deposit (see Brett, 1974). The primary interest in the North Evans for the paleontologist is the presence of large numbers of conodonts, arthrodire fish plates, cladodid shark teeth, and other fish remains. Thes conodonts and fish remains are phosphatic, and can thus be recovered from the rock by dissolution of the matrix with dilute acetic acid. The conodonts of the North Evans Ls have been extensively studied and figured by Bryant (1921). Buehler and Tesmer (1963) provide an extensive list of the conodont and fish remains in the North Evans/Genundewa combination. A description of the stratigraphic units at Section 1 has recently been published by Over et al. (1999).
References:
Bryant, W.L. (1921) The Genesee Conodonts. Buffalo
Soc. Nat. Sci. Bull. 13, No. 2.
Buehler, E.J., and Tesmer, I.H. (1963) Geology of Erie County. Buffalo Soc. Nat. Sci. Bull. 21, No. 3.
Grabau, A.W. (1898, 1899) Geology and Palaeontology of Eighteen Mile Creek and the Lake Shore Sections of Erie County, New York. Buffalo Soc. Nat. Sci. Bull. 6, Pt. I, Geology; Pt. 2, Palaeontology.
Kloc, G.J. (1983) Stratigraphic Distribution of Ammonoids from the Middle Devonian Ludlowville Formation in New York. Unpublished M.S. Dissertation, SUNY at Buffalo, 73 pp.
Over, D.J., Baird, G.C, and Kirchgasser, W.T. (1999) Frasnian (lower Upper Devonian) Geology of Western New York as Seen along Eighteen Mile Creek and Route 20A: Submarine Discontinuities, Gravity Flows, and Mass Extinction. NYSGA 71st Annual Meeting Field Trip Guidebook, SUNY Fredonia, October 1-3, 1999. Sun. B8-Sun. B16.
Last revised Oct. 9, 2002