Geologic Resource Evaluation Scoping Summary Marsh-Billings-Rockefeller National Historical Park & Saint-Gaudens National Historic Site Geologic Resources Division National Park Service The Geologic Resource Evaluation (GRE) Program provides each of 270 identified natural area National Park Service (NPS) units with a geologic scoping meeting, a digital geologic map, and a geologic resource evaluation report. Geologic scoping meetings generate an evaluation of the adequacy of existing geologic maps for resource management, provide an opportunity for discussion of park-specific geologic management issues and, if possible, include a site visit with local geologic experts. The purpose of these meetings is to identify geologic mapping coverage and needs, distinctive geologic processes and features, resource management issues, and potential monitoring and research needs. Outcomes of this scoping process are a scoping summary (this report), a digital geologic map, and a geologic resource evaluation report. The National Park Service held a GRE scoping meeting for Marsh-Billings-Rockefeller National Historical Park (MABI) and Saint-Gaudens National Historic Site (SAGA) on July 10, 2007 at the University of Massachusetts, Amherst. Tim Connors (NPS-GRD) facilitated the discussion of map coverage and Bruce Heise (NPS-GRD) led the discussion regarding geologic processes and features at the two units. Participants at the meeting included NPS staff from the parks, Northeast Temperate Network, and Geologic Resources Division, geologists from the University of Massachusetts, the Vermont Geological Survey (VGS), New Hampshire Geological Survey (NHGS), and Andover Geologic Consulting as well as cooperators from Colorado State University (see table 1). This scoping summary highlights the GRE scoping meeting for Marsh-Billings-Rockefeller National Historical Park and Saint-Gaudens National Historic Site including the geologic setting, the plan for providing digital geologic maps, prioritized lists of geologic resource management issues, descriptions of significant geologic features and processes, lists of recommendations and action items, and a record of meeting participants. Park and Geologic Setting Both Marsh-Billings-Rockefeller National Historic Site and Saint-Gaudens National Historic Site lie within the Connecticut River watershed encompassing some 643 and 148 acres, respectively. Marsh-Billings-Rockefeller National Historic Site, established on August 26, 1992 and open to the public since 1998, preserves the home and agrarian landscape of pioneer conservationist George Perkinds Marsh just west of the town of Woodstock, Vermont. This site is the headquarters for the Conservation Study Institute and contains the oldest managed forest in the United States. Marsh- Billings-Rockefeller National Historic Site is devoted to demonstrating conservation stewardship and forest management practices. Saint-Gaudens National Historic Site, authorized August 31, 1964, is the only NPS unit in New Hampshire, located just east of the Connecticut River. This site contains the home of sculptor Augustus Saint-Gaudens whose late 1800s to early 1900s works include the Shaw Memorial in Boston, Massachusetts. Lower Paleozoic metasedimentary and metavolcanic units dominate the bedrock geology of eastern Vermont and western New Hampshire. In the immediate vicinity of the two national historic sites, old Precambrian age rocks (exposed in the Green Mountains and Chester Dome) were thrust upward, deforming the overlying rocks creating folds with interference patterns during Paleozoic 1 mountain building events. Bedrock composition, geologic structures such as faults and upturned folds, glacial scouring, and differential erosion controlled the formation of the current topography in the area. Notable hills in the area include Mount Ascutney, Dingleton Hill, Mount Tom, Tinkham Hill, Mount Peg, and Hurricane Hill. A large regional fault, the Monroe thrust, separates these Lower Paleozoic rocks from the New Hampshire sequence to the east. The Connecticut River’s course appears to follow this geologic boundary. Further downstream, the river flows through Triassic extensional basins. During the last glacial advance of the Pleistocene Epoch, the Hudson- Champlain ice lobe scoured the area creating rounded hilltops. Upon glacial retreat, thick units of silt- and clay-rich till blanketed the landscape at Marsh-Billings-Rockefeller National Historic Site. In the Saint-Gaudens National Historic Site area, Glacial Lake Hitchcock inundated the re- excavated Connecticut River Valley leaving near shore deltaic and lacustrine deposits on the landscape. Marsh-Billings-Rockefeller National Historic Site sits on a ridgeline anchored on the east by Mount Tom, which rises more than 400 m (1,300 ft) above sea level. The site contains a large 14-acre pond (The Pogue) sitting in a gently sloping saddle. Large streams such as Barnard Brook, Gulf Stream, and Bridgewater Brook, in addition to local unnamed streams are part of the larger Ottauquechee River watershed. Steep slopes flank these waterways as they cut through the metamorphic bedrock. At Saint-Gaudens National Historic Site, Blow-Me-Down Brook and Blow-Me-Up Brook border the park on two sides flowing through the rolling hills of the forested uplands before merging on a broad floodplain just before the confluence with the Connecticut River. From its west-facing slope vantage point, Mount Ascutney dominates the view. Geologic Mapping for Marsh-Billings-Rockefeller National Historical Park and Saint-Gaudens National Historic Site During the scoping meeting Tim Connors (NPS-GRD) showed some of the main features of the GRE Program’s digital geologic maps, which reproduce all aspects of paper maps, including notes, legend, and cross sections, with the added benefit of GIS compatibility. The NPS GRE Geology- GIS Geodatabase Data Model incorporates the standards of digital map creation set for the GRE Program. Staff members digitize maps or convert digital data to the GRE digital geologic map model using ESRI ArcMap software. Final digital geologic map products include data in geodatabase, shapefile, and coverage format, layer files, FGDC-compliant metadata, and a Windows HelpFile that captures ancillary map data. Completed digital maps are available from the NPS Data Store at http://science.nature.nps.gov/nrdata/. When possible, the GRE program provides large scale (1:24,000) digital geologic map coverage for each park’s area of interest, usually composed of the 7.5-minute quadrangles that contain park lands (figure 1). Maps of this scale (and larger) are useful to resource management because they capture most geologic features of interest and are positionally accurate within 40 feet. The process of selecting maps for management use begins with the identification of existing geologic maps and mapping needs in vicinity of the park. Scoping session participants then select appropriate source maps for the digital geologic data to be derived by GRE staff as well as determine areas in need of further mapping or refinement. Tables 2 and 3 (at the end of this document) list the source maps chosen for Marsh-Billings-Rockefeller National Historical Park and Saint-Gaudens National Historic Site as well as any further action required to make these maps appropriate for inclusion. 2 Park resource management identified surficial and bedrock geologic maps as needed data sets. At present, large scale, digital geologic mapping exists for bedrock and surficial geology of the town of Woodstock, Vermont including the park area. This is an adequate extent for resource management at Marsh-Billings-Rockefeller National Historic Site. For Saint-Gaudens National Historic Site, 1:24,000-scale mapping needs persist for both bedrock and surficial geology. Park resource management determined coverage of the towns of Cornish, New Hampshire and Windsor, Vermont is adequate for their needs and entire 7.5-minute quadrangles are not necessary. The New Hampshire state map has coverage at 1:250,000 scale (contact: Lee Wilder), but this is likely too coarse for resource management. Unpublished surficial coverage may also exist for some parts of the area (contacts: Fred Larson at Norwich University and Jac Ridge at Tufts University). Tables 2 and 3 list the source maps chosen for Marsh-Billings-Rockefeller National Historic Site and Saint- Gaudens National Historic Site and mapping needs in certain quadrangles, in addition to a unique “GMAP ID” number assigned to each map by GRE staff for data management purposes, map scale, and action items. For the Marsh-Billings-Rockefeller National Historic Site, GRE staff used the following maps: • (74748) Thompson, Peter J., 2006, Bedrock Geologic Map of Woodstock, Vermont, Vermont Geological Survey, Open-File Report VG06-4, Plate 1 of 2, 1:24000 scale • (74749) DeSimone, David, 2006, Surficial Geologic Map of Woodstock, Vermont, Vermont Geological Survey, Open-File Report VG06-5, 1:24000 scale The completed MABI digital geologic map is now available from the NPS Data Store at the following address: http://science.nature.nps.gov/nrdata/quickoutput.cfm?type=ds&cat=geology&key=GRE&parkcode=MABI For the Saint-Gaudens National Historic Site, GRE staff remain undecided on which geologic maps best cover the SAGA area adequately, but the following maps may prove to be the currently best available: • (2344) Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., 1997, Bedrock geologic map of New Hampshire, U.S. Geological Survey, , 1:250000