Klein, A.J., Goldman, M.A., and Shah, A.K., 2018, Digital geologic map of the Elizabethtown Quadrangle, Essex County, New York: U.S. Geological Survey data release, https://doi.org/10.5066/F7J101P9.
Dr. Matthew S. Walton worked in the Adirondack Mountains during the summer with the New York State Geological Survey (NYSGS) between 1948 and 1956 while a faculty member at Yale University. His suite of hand-drafted and hand-colored geologic maps for the eastern Adirondacks were created over eight field seasons and recorded as unpublished manuscripts in the New York State Museum "Open File" archives (Walton, 1960). Many of these maps, including that of the Elizabethtown quadrangle, never underwent peer review, but they nonetheless provide the most detailed geologic information currently available for the area.
To produce this digital dataset, the map was first georegistered in ArcMap 10.4.1. The georegistration included adjustments for folds and stretching of the original paper map through comparisons to elevation contours provided in the USGS Elizabethtown, NY Quadrangle Topographic Map, 1955. ArcScan was then used to convert the raster into a vector-based feature layer.
Geologic units are presented as polygons, with units labeled according to Walton's original nomenclature. Descriptions of the geologic units, given by Walton in the original map, are included in the associated attribute table. A more detailed discussion of these units is provided in an unpublished text (Walton, 1966), also available in this dataset. We note that Walton did not distinguish ages, and all bedrock units are listed as "Precambrian." Areas that do not show bedrock units are depicted here as Quaternary cover, consistent with later regional maps.
Structural features and dikes are provided as line objects, while mines are provided as points. The 1960 map adheres to an older style of symbology which is not used in more modern geologic maps. For example, what appears as the modern symbol for a thrust fault (a solid black line with black triangular barbs) actually represents a geologic contact, and the barbs depict an interpreted dip range (less than 45 degrees, greater than 45 degrees, and 90 degrees) and dip direction. To make the map more consistent with modern usage the barbs have been left off of the digitized map, but they may be viewed on the scanned geotiff of the original map (included here). Walton's symbology for faults and shear zones is maintained in this dataset as it reflects modern-day usage (straight, bold lines). A scanned copy of Walton's accompanying notes is included; these notes also apply to maps of the Paradox Lake, Port Henry, and Ticonderoga 15' quadrangles (Walton, 1966).
References:
Walton, M.S., 1960, Geologic map of the Elizabethtown quadrangle, New York: New York State Geological Survey Open File No. 1g235, scale 1:62,500, 1 hand-colored sheet.
Walton, Matt, 1966, Explanation for bedrock maps of the Paradox Lake, Elizabethtown, Port Henry and Ticonderoga 15' quadrangles, and contained 7-1/2' quadrangles: New York State Geological Survey Open File No. 1m462, unpublished manuscript, 47 p.
