robert z selden jr, archaeology, archeology, geometric morphometric, ceramic, analysis, mathematics, statistics, 3d, 3d scan

On Missing Data: 3D Morphometrics of Ceramic Artifacts

In the sample of complete and reconstructed Caddo NAGPRA vessels from the Turner Collection, many were found to include missing data (most often from sherds that were never recovered). While we have not been scanning vessels with large amounts of missing data–must be very close to complete–we needed to test the various methods by which those missing data can be reconstructed. Further, we wanted to explore the deviation of the results from the original mesh.

To do this, we used a whole/intact vessel from the Ellis Collection, cut a hole in the mesh, then used one of three functions in Geomagic Design X (defeature, fill holes, and edit boundaries) to generate new data over that area. Shifting over to Geomagic Verify, we use the original mesh as the nominal data, and the scan with missing data as the scan data to calculate the deviation between the two.

EditBoundaries_D1313

Results from the edit boundaries function.

FillHoles_D1313

Results from the fill holes function.

Defeature_D1313

Results from the defeature function.

In this case, the defeature function resulted in the lowest deviation from the original surface; however, this is not always the case. Each of the three functions was found to be successful in addressing missing data, and all warrant exploration on areas of the vessel that are geometrically similar to that where the missing data occurs to identify which function works best in each individual case. Additionally, the results of these comparisons should augment any publication as supplementary data.

My work with geometric morphometrics employs landmarks and sliding adaptive semilandmarks along a spline to compare various aspects of vessel shape, and selecting the correct function to address missing data in a sample could potentially impact those results. Through making an informed decision regarding which function to implement, we are mitigating a–potentially–higher degree of error within our sample.

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The Antiquities Code of Texas: The Creation and First Decades (Denton)

The Antiquities Code of Texas was one of the first state-based historic preservation laws created in the United States and it is still one of the strongest laws of its kind. The Antiquities Code was created as a reaction to shipwreck treasure salvagers that found remains of the 1554 Spanish Fleet that had swept ashore in a hurricane off the coast of South Padre Island. The treasure hunters found the remains of one of those vessels and starting removing those artifacts including silver and gold coins and taking them out of state. Had the salvagers been from Galveston or some other Texas town, it’s very possible that the Antiquities Code would have never been written, but the fact that the salvagers were from Indiana (think “damn Yankees”) the State of Texas stepped in and sued the treasure hunters for taking artifacts that belonged to the citizens of Texas. Jack Giberson, the General Council and Deputy Land Commissioner with the General Land Office of Texas, was instrumental in the efforts associated with the 1554 shipwreck case, and for many years after he proudly told the story of when he and three Texas Rangers flew to Indiana to confiscate the artifacts and return them to Texas.

Jack Giberson and a few state legislators were also the first state officials to recognize that the State of Texas did not have an adequate law in place to protect publicly owned historic resources. Therefore, those individuals worked closely with Truett Latimer, the executive director of the Texas Historical Commission (THC), and Curtis Tunnell, the State Archeologist, to figure out how to correct this problem. The result was, the 61st Texas Legislature passed the new Antiquities Code (Code) through both houses in the spring of 1969 and it was signed by Governor Preston Smith and went into effect on September 1, 1969. Its enactment has changed the way historic resources on non-federal public lands in Texas have been managed ever since.

TexasGovernorPrestonSmithFormer Texas Governor Preston Smith
Link to original image here.

The wording of the original Code was fairly similar to a law that the State of Florida had in place at the time. The original Code allowed legal treasure hunting off the Texas coast, provided that the treasure salvage investigations were performed under the direction of a professional archeologist, and the State also got to decide which artifacts would be retained by the State. The Code also protected all publicly owned archeological resources in the state and it was and still is a very unique law that continues to be a model for other states. The Code was never intended to cover resources on private property without the expressed written consent of the private land owners, and there is no question that this aspect of the law will never change.

The original Code also created the concept of State Archeological Landmarks and a new state commission known as the Texas Antiquities Committee (TAC) whose job it was to administer the Code. From the beginning however, the staff of the Texas Historical Commission (THC) functioned as the staff of the TAC and the State Archeologist and Executive Director of the THC served on the TAC board.

The first archeological investigations performed under the jurisdiction of the Antiquities Code were performed by Dr. Frank Weir, head archeologist for the Texas Highway Department (currently known as the Texas Department of Transportation) in 1970. That same year, the San Antonio Missions were also designated as the first State Archeological Landmarks (SAL).

San-Antonio-Mission
Mission San Jose y San Miguel de Aguayo in San Antonio, Texas.
Link to original image here.

During the first 10 years after the creation of the Code approximately 250 permits were issued for archeological and historic structure investigations on public lands, and approximately 20 sites and buildings were designated as landmarks during this period. During the second decade, approximately 700 permits were issued and over 1500 sites and buildings were designated as landmarks.

The 68th Texas Legislature removed of treasure salvage provisions in 1983, and limits on the protection of historic buildings were added in 1987. Additionally, clarifications about the responsibilities of political subdivisions of the State were added in 1995. The Texas Antiquities Committee was dissolved in 1995, and the THC Commissioners took over direct administration of Code.

About the Author

Mark Denton is an Archaeologist, and Program Coordinator at the Texas Historical Commission in Austin, Texas.

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Article Published in Advances in Archaeological Practice

The article was recently published in the current edition of Advances in Archaeological Practice, and is focused upon the documentation and analysis of Caddo NAGPRA vessels from the Vanderpool site in East Texas. This effort was the pilot study for a much larger/broader study of Caddo ceramic vessels that will begin later this summer. We are very grateful for the comments and constructive criticisms that developed in our discussion of this project, and hope that you enjoy the article.

AAP

The article is available for download on the Advances in Archaeological Practice website (here), and in our institutional repository (here).

A special thanks to Mr. Robert Cast of the Caddo Nation of Oklahoma and Mrs. Patti Haskins and the Gregg County Historical Museum for allowing access to this collection of NAGPRA vessels.

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