Friday, March 22, 2013

Winter Testing at Fort Hunter


 The Road to Fort Hunter


Fort Hunter Mansion and a portion of  the trench excavation 
          

We are taking a break this week from our travels through Pennsylvania by county to report on our testing over the past two weeks at Fort Hunter. Despite the miserable weather, with no activities planned for the Mansion, it was a perfect time to dig up the front yard and continue the search for the elusive stockade trench and ditch that likely surrounded the fort. The discovery of these features would obviously simplify our efforts to locate other fort features. Anything dug into the ground, especially the size of a ditch or entrenchment surrounding the fort, should be visible as disturbed soil. Thus far, the exact location and dimensions of the fort have not been recorded in any documents that we have researched. General maps and descriptions place the fort on the south side of Fishing Creek and at the juncture with the Susquehanna River. This is also the most obvious location for a fort if it is to be easily accessible by boat and to have a commanding view of the river.
Since beginning the investigation of the French and Indian War occupation at Fort Hunter, several excavation units have been opened east of the mansion towards the front of the house (hereafter denoted as the front yard) and north of the mansion around the icehouse (denoted as the backyard). This latter area has produced nearly all of the artifacts and features recovered so far dating from the mid-18th century.

Block excavation unit adjacent to the Ice House


Over the years, several trenches have been excavated in the front yard but these produced few artifacts and the stratigraphy (layering of the soils) was complex and confusing. In 2011 and 2012, a road or ditch-like feature was discovered in the front yard. In cross-section, it appeared as if a thirty foot wide trench had been dug sometime in the past and later backfilled to be level with the present ground surface.  We decided to investigate this area with additional backhoe trenches. Specifically, a number of test trenches were configured in order to maximize our ability to map the horizontal placement of this road/ditch feature. In addition, the front yard is a wide flat area that could produce other Fort related features and this was an opportunity to conduct a comprehensive survey of this area.


Excavations in 2010 uncovered this cobble area, prompting  us to                                            conduct this trench excavation

With the indulgence of our hosts, Fort Hunter Mansion and Park, we excavated over 400 feet of trenches encompassing nine different locations. Our excellent backhoe operator, Corry Harner was accompanied by his nephew, Caleb Kickes and they were both excited to uncover new and interesting information about the history of central Pennsylvania.

Corry Harner skillfully opening our trench

Caleb (in black) scanning the back dirt for artifacts

Plan map of trench excavations

A total of nine trenches were dug running perpendicular and parallel to the river. The goal in placing these trenches was to fully expose the area surrounding our ditch/road feature in order to better define and interpret this feature. Additionally, these trenches allowed for further exploration of a line of soil auger tests (hand drilled soil testing device) implemented in the fall of 2012.  Auger tests had revealed a natural profile, meaning undisturbed by historic activities. These auger tests produced a few prehistoric artifacts, including fire-cracked-rock, flakes and a Late Archaic (4300-6000 years ago) Brewerton side-notched spear point.  Trenches placed along this line of auger tests revealed the presence of large rocks which may represent the remains of an historic structure that was possibly fort related.  This trench was excavated over a distance of 120 feet to further investigate these rocks and aid in determining the limits of the road/ditch. Additional trenches were placed to investigate disturbances  uncovered in our original trench that may be related to the stockade.


Trench profile


Taking profile measurements in trench #1





Results:     
      The trenching produced some very interesting stratigraphy suggesting an oval shaped basin that is approximately one to three feet deep, 40 feet wide (east–west) and 170 feet long (north-south). The basin is defined by a layer of dark soil that slopes down in profile around its edge to approximately two feet deep in the center and lies on top of a gray sandy hardpan material. The deepest section of the basin measured less than 18 feet wide and approximately 160 feet long. The gray hardpan exhibits iron staining and in most places a ¼ inch thick layer of iron concretion marks the top of this soil. The gray color frequently represents a soil that was formed in a low oxygen environment such as under water and the iron deposits are also compatible with a surface that was frequently covered with water. Rusted iron artifacts, including an ox shoe and square cut nails were recovered at the top of the gray hardpan.
Along the eastern edge of the depression we found a post mold in Trench #1. This discovery produced a great deal of excitement because it was very similar to the post molds that have been found in stockade trenches at other French and Indian War forts such as Fort Loudoun in Franklin County. The stain was very clear in the profile and the image of where the post had been placed was clearly defined by the edge of the post hole and two large cobbles that had been intentionally placed in the hole to support the post. Rocks used as supports for stockade posts are another feature common in stockade trenches.



Post mold exposed in profile. Note the two
large cobbles at base of post mold.




We called Corry in with his “mini-excavator” to remove the topsoil in an approximate ten foot unit around the post mold. Surprisingly, the post mold produced both prehistoric and historic artifacts but none from the mid 18th century. After extensive troweling and shoveling, only one other possible post mold was exposed. Alas! This does not appear to be a stockade line but we are unsure what it represents.
Finally, numerous prehistoric and historic artifacts, especially heavily rusted nails and other rusted iron objects were recovered from the trenches closest to our 2011 trench.  In contrast, the more southern trenches produced very few artifacts of either historic or prehistoric age. Based on the quantity of artifacts and features, most of the archaeology continues to be focused within 50 feet of the mansion.


The sun illuminates our high school "shadow", Nick Beard.
Nick endured the cold temps and assisted with measuring and mapping

Callie took on the task of operating our total station,
while Liz assists in recording measurements 

Dr. Frank Vento, a Geomorphologist from Clarion University of Pennsylvania, visited the site on 3/20/13. Based on a general description of the soils, he was able to summarize the formation of the stratigraphy in this section of the yard including the road/ditch feature. He concluded that the gray hardpan marks a ground surface that was exposed for some period of time probably during the 18th and early 19th centuries. He also noted that it was frequently covered with water thereby confirming our interpretation that it was this created in a low oxygen environment. Along with the presence of organic material, the soil overtime turned a gray color. The hard packed nature of the soil was likely caused by heavy wagon loads being rolled over this surface. According to Dr. Vento, this feature most likely represents a road. By the late 19th century, the depression was partially filled in by erosion from the surrounding sediments or by flooding. Later landscaping by the residents of the mansion completed the backfilling of this feature so that there is now no evidence of its existence on the surface today.

Conclusion:
     As stated above, the most likely origin of the basin-like structure is that it was a road. Sometime, possibly during the 18th century, the road was dug through this area. It could be a product of the fort period or of the subsequent owners’ (Archibald McAllister). As well, it could represent the original road north along the river (the original route 322) noted on 18th century maps. The perplexing issue is why?  Why excavate a 40 foot wide and two foot deep area for a road when the existing ground surface is relatively flat? This created a basin like structure that collected water as documented by the gray soil and iron deposits. Sections of the gray hardpan are layered or paved with pebbles possibly to create a more stable roadbed. However, other areas are not paved and this would have created a very muddy pathway causing problems for wagons.
Based on the presence of historic artifacts at the bottom of the feature, the depression was filled during historic times. The co-mingled presence of large numbers of prehistoric artifacts in these soils suggests they came from the immediate vicinity and probably from the topsoil surrounding the basin. Another possibility is that the road-like feature remained open well into the early 19th century when McAllister filled it in by grading topsoil from the yard area around his house. This scenario would explain the relatively thin layer of topsoil that presently covers the front yard except in those areas over the depression where the topsoil is significantly thicker.
As is usually the case in archaeology, excavation and analysis solve some problems but create others. Considering its location, this feature could have been used to haul supplies to Fort Hunter that were loaded onto canoes and transported to Fort Augusta at present day Sunbury.  The road may lead to an entrance or gate into the fort. Therefore, it is important to recover artifacts that will directly date this feature because it could just as easily be part of the later (non-fort related) McAllister occupation. In addition, there is the nagging question of why dig a road that collected water? 
The mystery continues but we have a pretty good working hypothesis. The front yard was significantly altered through landscaping sometime in the past. It is possible that this process destroyed or at the very least modified the structural evidence of the stockade and ditch/entrenchments that surrounded the fort. The only place that has produced indisputable evidence of the fort is in the back yard and that will be the focus of subsequent investigations. The topsoil in this area contains high densities of historic period artifacts from the fort period and is also significantly thicker than the topsoil in the front yard. Here, the stockade and entrenchments may have been covered by later landscaping, hopefully preserving them for our discovery. In September, we will continue to follow the road towards the back yard in hopes of locating its destination and explaining why it was dug.


How soon till spring? 

                         



For more information, visit PAarchaeology.state.pa.us or the Hall of Anthropology and Archaeology at The State Museum of Pennsylvania .

No comments:

Post a Comment

Post a Comment