Page 42 - Maryland Historical Trust - Archaeology Colonial MD

figure 29
The chapel foundation as uncovered
in 1990.
should be saved. Stone agreed and shell samples began being routinely collected from well-dated contexts. Seven years would pass but in 1980, an ecologist named Brett Kent was recruited to explore the potential information oyster shells might yield. Kent’s work revealed that the shells contained a variety of environmental information about bottom conditions, water salinity, collec- tion habitat, and their size could reflect the level of harvesting pressure.18 One notable discovery came from comparing the shells from different time periods at St. John’s. Shell size displayed a dramatic reduction by the late 1600s, but also a rebound in the latest deposits at the site. These changes seem to correspond closely to the shifts in human population size at St. Mary’s City. The population grew gradually over the 17th century and several hundred people were living there by 1690. However, when the government was moved to Annapolis in 1695, the population plummet- ed and St. Mary’s was largely abandoned. This change in oyster size may be due to overexploita- tion of the oyster populations in the last half of the 17th-century, the first archaeological evi- dence for human impact upon a Chesapeake Bay resource. Once harvesting pressure was relieved, the shellfish had the time to grow larger. Archae- ological oyster shells remain a significant resource
for estuarine environmental history.19
In a real sense, the excavations at St. John’s
provided the foundation for 17th-century his- torical archaeology in Maryland. It was the first source of insight about the vernacular architec- ture, landscape, material culture, and foodways in the early colony. It also set an excavation stan- dard by reliance upon the same measuring system used by the colonists (English feet and inches), instead of the French Revolution’s system of dec- imal metric measurement. This facilitated analysis of buildings and yards since they had been laid out using English measures. For example, 8 and 10 foot bays became common in buildings and knowing this allows excavators to predict post locations when attempting to define a structure. Similarly, fence posts were often placed at 8, 10 or 12 foot intervals, many gates were 3 feet wide and wall studs often placed at 2.5 foot increments. St. John’s also showed that plowzone soils and the artifacts they contain have much research value. Despite agrarian disturbance over several centu- ries, much of the archaeological record of sites is found in the plowed soil. At a minimum, sam- pling the plowzone before grading it away is now seen as a necessary procedure, unlike in the 1970s. Other procedures such as protecting exposed
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