Research Update 3: The Last Shell Has Finally Come

With thousands of oysters to analyze at the start of the summer, the end looked like it would never come.  However, I have officially finished analyzing every precontact shell in my collection!  Now that I have finished my data collection, it is time to begin exploratory data analysis, looking for trends in the results that tell interesting stories.  This has been my main objective of this past week, and likely the coming week.  At the start of this week, Professor Gallivan introduced me to a statistical software system called SPSS.  We debated over whether I could conduct my data analysis through Excel or SPSS.  However, due to my lack of knowledge on both platforms, it was decided I should put my effort into learning SPSS since I would likely use it more frequently in the future.  The first day or two of exploring SPSS left me very confused.  The initial process of data entry on SPSS is more complicated them in Excel, as there are two pages for each data set to manage–Data View and Variable View.  However, the more I have experimented with the software, the more comfortable I have become with it.  Over the week, I have input all my data into the system.  Then I went through all my data doing an accuracy check to ensure every column was completely filled in and there were no values or designations that seemed obscure from the rest of the measurements.  I only had a few spots that left me with questions, and for those, I went back through my oyster collection and reanalyzed the shells in question for all attributes.  After double-checking all my data, I created a table that simplified the data setup from a per shell factor of analysis to a “feature” factor of analysis.  Since there were over two thousand individual shells analyzed and only 14 feature they originated from, determining important trends between features is much easier than between shells.  With this being said, I calculated the mean, or average, of all the shells found in each feature for all of the attributes measured–mass, length, height, height-length ratio (HLR), presence or absence of an attachment scar, presence or absence of parasitism, percentage of parasitism, parasitism on attachment scar, and left-valve concavity (LVC).  By looking at the table, I have been able to identify possible trends to further explore with histograms and box plots that show the actual variations between the features.  One of the trends that I am extremely interested in is the relationship between shell size and parasite presence with the type of roasting pit in which they came from.  The site report for site 44YO0797 identified two types of roasting pits, some that show evidence of heavy firing and others that do not.  Currently, it appears that the roasting pits that have lesser evidence of firing contained the larger, more likely offshore oysters, and I wonder if this has anything to do with preservation techniques of the Native American.  Site 44YO0797 was a secondary base camp for the Native Americans used for gathering supplies, so I am curious in exploring the possibility that the roasting pits with evidence of firing that contained smaller, near-shore shells because those were the oysters eaten on-site, while the roasting pits without evidence of firing had more larger offshore oysters because they were preserved for later use.  At this point, this is merely a theory that I hope to explore more with continued data analysis.  Additionally, I plan to compare my findings to those of Jessie Jenkins and Martin Gallivan who conducted a similar study of oyster shells at a different Native American site along the York River that was a primary settlement instead of a secondary supply gathering camp.

Research Update 2: Oh So Many Oysters!

My first three weeks of lab work have gone very smoothly!  The first week I started off as the only student in the lab which left for long and quiet days.  Now there are up to six other people in the lab with me leaving for a much more talkative and bustling day!  I have officially analyzed 1600 shells which is incredible; at the start of my work that seemed so far away!  Most of the features I have analyzed have followed the patterns of my hypothesis that most of the oysters from site 44YO0797 are intertidal oysters, meaning that are generally small, rounded (low HLR), lack sponge parasitism, not deeply cupped (low LVC), and have attachment scars indicative of nearshore substrates.  However, early this week I discovered four features that veer from this trend—features 1064, 1062, 1063 and 1065.  While these features still contain a number of small, likely intertidal shells, they revealed a large supply of what have been identified as subtidal oysters.  They are identified as such because the oysters are generally large, elongated (high HLR), have a high percentage of sponge parasitism, and are deeply cupped (high LVC).   The site report for 44YO0797 states that “features 1062, 1063, and 1064 were all also extremely similar in appearance.  These features were also located in a straight line, and were spaced about even distances apart: Features 1062 and 1063 were 3.3’ apart center to center, and 1.3’ apart at their nearest points. Features 1063 and 1064 were 3.8’ apart center to center, but also 1.3’ apart at their nearest points” (186).  This allows for the estimation that these three features were contemporary, meaning the remains of a single occupation at the site, likely Middle Woodland.  Below are some images of the larger shells found.

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Research Update 1: Time to get Oystering

Summer is going by so quickly; I cannot believe it is already July!  I spent the first half of the summer completing an archaeological field school under my anthropology adviser, Martin Gallivan, at a Native American settlement called Kiskiak at the York County Naval Weapons station that dated to the Middle Woodland II (A.D. 200 to 900) period.  There I learned all about the techniques and process that go into an archaeological excavation, and then excavated some of my own Test Units looking for evidence of Native American artifacts and disturbances in the surrounding environment.  Simultaneously with my field school, I was conducting preliminary reading and collecting background information for my summer research project.  I am conducting research in a field I like to refer to as either Environmental Archaeology or Historical Ecology, with an emphasis on looking to past populations that lived sustainability with the environment for many centuries, to see how they were able to do so, and if any of their techniques could be applied to our modern society to lessen the damage we are putting on our current environment.  The project I am working on this summer looks at oyster shells from a Middle Woodland II site, similar to the one I conducted my field work on, in York County along Carters Creek, an off shoot of the York River.  The site is referred to as 44YO0797 in the archaeological record.  44YO0797 has been interpreted to be a small, seasonal settlement the Native Americans would come to for parts of the year to collect supplies and food.  There is record that the site was inhabited by native populations during the Middle Woodland period (500 B.C. to A.D. 900) and the Late Woodland period (A.D. 900 to 1607), and a historic occupation during the late 18th and early 19th centuries.  Archaeological excavations unearthed large numbers of oyster shell at the site indicating that the area was well-established as an oyster harvesting site for both native population and later colonists.  For my project, I am analyzing the shells uncovered at site 44YO0797 to determine the location of harvest of the shells.  The James River Institute of Archaeology has provided me with several boxes of oyster shells that have been dated to be either pre-contact (harvested by the Native Americans) or post-contact (harvested by the colonists).  The historical record tells us that native populations were able to harvest oysters suitably on a millennia scale, and that population numbers and oyster sizes only began to drastically decline once colonization began, and are continuing to decline today.  My research questions are based around determining how the native populations were able to harvest oysters so long without dramatically harming the populations.  There are some obvious answers such as the natives had smaller populations, less technology, less polluted land and water ways, then the colonists had, and we have today.  However, while doing my background reading on native oyster harvesting, I came across the assertion that native populations mainly harvested intertidal oysters, and only harvested the off-shore, subtidal oysters for special feasting and religious occasions.  Thus the subtidal oysters remained primarily untouched and acted as a parent reef to the intertidal oyster beds.  In my shell analysis so far I have been looking at several characteristic to determine if the oyster was harvested from a subtidal or intertidal reef, including height of shell, length of shell, height to length ratio, concavity of shell, presence or absence of attachment scar, presence of parasite boring holes and what type of parasite.  From my analysis so far I have determined a trend that the shells dating to post-contact are usually determined to be subtidal, while the shells dating to pre-contact are usually determine to be intertidal.  This is a trend I hope to see continue to see as I analyze more shells.  However, I have only looked at a small fraction of the oyster shell and still have hundreds to go!  I cannot wait to see what the rest of the summer holds for my research!

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