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Site name: Sylvester Manor
A Northern Plantation
Comments: A plantation established in 1651 by Nathaniel and Grizzell
Sylvester to supply provisions for two sugar plantations in Barbados covered all
of Shelter Island, a small island off the eastern tip of Long Island.
Documentary and archaeological evidence reveals enslaved Africans,
Native Americans, English and Dutch working at the plantation. A 250 acre core of
the first plantation is known as Sylvester Manor today, which includes the circa
1735 manor house, Quaker and African burial grounds, cottages, farm buildings, and
a large two acre garden. As part of Dr. Steve Mrozowski's (U Mass-Boston) on-going project at
this site complex, geophysical investigations were performed to ascertain the nature
and extent of buried cultural features. The results reveal a site of great
complexity probably stemming from its importance as a center of major trade activity.
Many of these findings have been corroborated by
U Mass-Boston's excavation efforts.
Type of survey: Resistivity; Instrument: Geoscan Research RM-15 & MPX-15 (0.25 & 0.5 m probe spacings); Prospection depth: 0.25 m; Sampling interval: 0.5 x 0.5 m; Area surveyed: 5,800 m2; Dates of survey: 6/00.
A host of linear and rectangular features are suggested by the resistance data.
In general, numerous linear
high resistance features are indicated (in black in the figures) that point to
probable stone walls or foundation lines, pavements, or floors. The area to the
west and north of the Manor is particularly rich in such features, suggestive of
numerous former structures and constructions, built and organized with much regularity
suggestive of an organized plan, almost like a small village. Warehouses and
outbuildings are a distinct possibility. Some of the resistance highs to the
southeast of the Manor probably represent the outlines of former garden features
or their organizational components. The resistance data also reveal a many
former roads or trails as low resistance linear features (white in the figures).
Type of survey: Magnetic gradiometry; Instrument: Geoscan Research FM-36 fluxgate gradiometer; Prospection depth: up to 1.5 m; Sampling interval: 0.5 x 0.25 m; Area surveyed: 6,500 m2; Dates of survey: 6/00.
The magnetic data suffer from the distribution of much modern ferrous material,
such as iron stakes used to anchor tree-support wires (these are indicated as
triplets of magnetic data spikes throughout the figure). The magnetic map also
indicates a general distribution of ferrous artifacts, many of which are probably
historic and can be located with accuracy using the map. One such large magnetic
feature is an historic 17th century cannon, for example, that was excavated some
years ago during normal property improvements. An area of particular
interest magnetically is immediately to the north of the Manor where extremely noisy
data are indicated, suggesting intensive activity and much iron, probably in the
form of a midden or dumping ground. A number of linear alignments can also be seen
in this area that may suggest the placement of more magnetic building stones or
possible roadways or trails (the nature of some of these can be determined through a comparison
against the resistance data).
Type of survey: Ground penetrating radar; Instrument: Geophysical Survey Systems, Inc., SIR-2000; Prospection depth: about 1.5 m; Sampling interval: 0.5 x 0.02 m; Area surveyed: 1,100 m2; Dates of survey: 6/00.
Four specially placed GPR surveys were conducted at Sylvester Manor, one of which is
illustrated here. This study block, measuring 9 x 15 m, was acquired in the west side
of an "oval" driveway, adjacent to a 1999 excavation pit.
The results are very exciting and suggest the future promise of the GPR data at this
site. In the associated figure, a near-surface "slice" through the GPR transects
(depth about 20-40 cm) reveals a structure that is clearly rectangular
in shape, suggesting a human construction (possibly a pavement, foundation, old roadway,
rectangular ditch, etc.). At a slightly deeper level in the GPR data (not illustrated) a
similar feature, square in shape, occurs, suggesting a lower construction.
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(updated: 10/00)