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GEOREF RECORD

Late Tertiary floral assemblage from upland gravel deposits of the southern Maryland coastal plain

Lucy McCartan, Bruce H. Tiffney, Jack A. Wolfe, Thomas A. Ager, Scott L. Wing, Leslie A. Sirkin, Lauck W. Ward and James Brooks
Late Tertiary floral assemblage from upland gravel deposits of the southern Maryland coastal plain
Geology (Boulder) (April 1990) 18 (4): 311-314

Abstract

A diverse flora has been discovered in a dark clay lens in upland gravel in southern Maryland near Brandywine. More than 49 taxa have been identified in the assemblage, which includes leaves, seeds, fruits, pollen, and a Taxodium (bald cypress) trunk. The vegetation is dominated by deciduous trees and vines. Four taxa are now absent from North America but survive elsewhere; one is extinct. A late Miocene age and warm-temperate climate are inferred from the flora. The clay lens probably represents a cutoff distributary in the extensive braided stream system that covered the area and is unique in Maryland. Similar dark clays have been described from Miocene sands and gravels in New Jersey. The Brandywine flora is the first direct evidence of the Miocene age of part of the fluvial upland deposits of Maryland. On the basis of the age inferred from the flora, the Brandywine deposit is correlated with the St. Marys Formation or the Eastover Formation, which are upper Miocene shelly marine units south and southeast of Brandywine.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 18
Serial Issue: 4
Title: Late Tertiary floral assemblage from upland gravel deposits of the southern Maryland coastal plain
Affiliation: U. S. Geol. Surv., Reston, VA, United States
Pages: 311-314
Published: 199004
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 28
Accession Number: 1990-033753
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch maps
N38°31'60" - N39°07'60", W77°04'60" - W76°40'00"
Secondary Affiliation: Univ. Calif., USA, United StatesSmithson. Inst., USA, United StatesAdelphi Univ., USA, United StatesVa. Mus. Nat. Hist., USA, United StatesMd. Geol. Surv., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1990
Program Name: USGSOPNon-USGS publications with USGS authors
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