Saturday, July 12, 2014

House Wall and Clay Floor

On Thursday we discovered evidence that the curious clay layer may have served as floors for dwellings.  A careful examination of the clay floor exposed in unit 498N 512E revealed an arc of post molds running along the edge of the floor.  These posts measure about 5 to 7 cm (1.5 to 2.5 inches) in diameter and penetrate through the floor.  The white dots in the image below mark these post molds.  The red areas are heat-oxidized areas of the floor; most likely places where fires were made.  The dark soil area on the left (west) represent where shallow pit features were dug, parts of which cut out small sections of the floor.  We are not sure what these pits were used for, but they contain significant amounts of animal bone and some fire-cracked rock.
One final feature of note was found in the southeast corner of the excavation unit (lower right).  This small, dark, shallow pit cut through a burned area of the floor, which tells us that it definitely post-dates the creation--and maybe occupation--of the dwelling that was built here four millennium ago.

Saturday, July 5, 2014

Finding the Clay Surface

This past Thursday, we found the base of the midden in unit 500N 512E at about 55 cm bd.  In the process, we uncovered the unusual yellow clay layer first discovered in 2008.  At that time we thought this clay was the natural subsoil that underlies the midden across the site.  Instead, it turned out to be a cultural surface resulting from the human occupation of the site.  We know this because beneath the yellow clay is an organic soil stratum which contains prehistoric cultural material.  We are not yet sure how this clay layer was created.  It may be the backdirt from digging deep pits dug nearby that penetrated the natural sandy clay subsoil.  But it may instead represent a deliberately created floor or working surface.  If so, then its presence shows that the Late Archaic inhabitants of this site took time to modify their settlement in a way that would last some time.  The image below shows the clay stratum and a large pit feature that appears to cut through this layer.

Next door, in unit 498N 512E, the dark organic midden soil was still being encountered.  Deer bone and antler, and carbonized nutshells are being found in abundance.  Among the finds was the base of a large flint drill.  On Friday, a drill tip was found near where the base turned up.  Not surprisingly, the two fragments fit together to form a long tool that measures about 12 cm (4.5 in) in length as shown below.  This exceptional tool was most likely complete when lost or stored at the Late Archaic campsite.

Wednesday, July 2, 2014

Tracing the Midden

Last week's rains set us back a bit, but this week has been relatively dry, and we have accomplished quite a bit.   Yesterday, we completed our shovel-test survey of the site with the help of youngsters in a Museum Archaeology program.  Eight eager students busily shoveled, troweled, and screened until the job was complete. 

We found few artifacts and virtually no midden deposits, but this was ok, at least for me, since we expected to be working at the very southern edge of the site.  So, the lack of discoveries was exactly what I expected.  The information from this survey will be very useful for understanding the diversity and locations of activities carried out by the prehistoric inhabitants of Burrell Orchard.   With the measurements taken during the excavation of each shovel-test unit, I was able to construct a map showing the depths of the midden deposits across the site.  As shown below, this map reveals a slightly curving distribution of deep deposits, some extending to more than 80 cm beneath the surface. 

As it happens, our current excavation units are situated within some of the deepest deposits on the site.  In future seasons, we will test areas of more shallow midden to better understand what was going on in places of less intense activities.

Thursday, June 26, 2014

Stratified Bones and Stones

After yesterday's rain, we were able to resume normal excavations today.  We continued to remove layers of midden soil at about 5 cm for each level.  This is slow-going but necessary to preserve the fine contexts of the artifacts and other cultural remains that are turning up.  We are still finding large quantities of fire-cracked rock and flint debris but also increasing amounts of animal bone.  Up to now, we found mostly heavily burned (calcined) bone fragments but over the last two days more unburned bone from several different kinds of animals have turned up.  Much of this is deer bone (see below), but today we found the complete lower jaw of a muskrat and some leg bones of another small mammal.  Most of this bone is coming from unit 500N 512E at the south edge of the old orchard. Surprisingly, flint tool debris and even FCR are scarce at the 40 cm level of this unit.

A nearly complete projectile point was found in unit 490N 497.5E.  As seen in this image, the end of the stemmed base is missing.

The two features I described in my last post are becoming much more distinct, along with more fragments of the siltstone slab "pavements."  The oxidize clay feature (no. 14-1) was sectioned late

this afternoon and was found to be a rather thin layer of burned midden sediment.  Underneath is another siltstone slab as shown below.  Here is a good example of two separate activities (fire-making and stone deposition) separated by only a few centimeters of soil deposition.  This truly is a well-stratified site!

Monday, June 23, 2014

Features Appearing

Last Friday we continued excavation in the 2x2 meter units.  It is a slow go, because the midden soil is rather high in clay content and loaded with fire-cracked rocks.  We have abandoned shovels all together in favor of trowels and brushes.   Several possible features have appeared on the floor of unit 498N 512E.  The image below shows that current floor at about 35 cm below datum.  You can see we have divided it into quadrants, which makes it much easier to take down the floor at different rates as needed and to more accurately provenience (locate) what we find.

The most obvious feature in this image is the large slab of siltstone in the upper left corner (SW quad).  Similar clusters of rock slabs were found in several  units in 2008 and their purposes remain uncertain.  They may have served as surfaces for preparing food or other activities.  In the lower left (SE quad) you can just see a brown-orange patch of oxidized soil (just above the upper left corner of our chalk board).  At first we thought this was a clay lens, but now I suspect it is an area of the midden deposit that was heated and hardened.  Perhaps this is an area where a fire was made and then the charcoal and ash were removed, perhaps by plowing.   In any case, these two features most likely represent a 'living surface', that is a level in the midden on which activities took place.  Finally, in the upper left corner of the lower right (NE) quad, near where the strings come together, is a rectangular patch of soil containing lots of charcoal.   This may represent the remains of a hearth feature or maybe just a lens of redeposited hearth contents.   Don't know what all this means yet, but finding any kinds of discrete features in the otherwise very homogeneous midden will help us better understand the sequence of occupations at Burrell Orchard.

Thursday, June 19, 2014

Digging Down To the Midden

Over the last two days at Burrell Orchard, we completed our shovel-testing and began work on three 2x2meter units near the edge of the old orchard.  Two of these units were placed adjacent to a 2x2 opened in 2008 that penetrated through the midden deposits and exposed a layer of yellow-brown clay.  This layer may represent a house floor similar to ones that have been recorded on Late Archaic sites in Illinois and Kentucky.   Or it could simply be subsoil backdirt from the digging of pits below the midden, but further work will tell.

As we removed the plow zone soils today, several interesting discoveries were made.  A nearly complete, stemmed lanceolate projectile point was found in the upper layers of the midden in Unit 490N 497.5E.  As shown below, this point is only missing its tip.  It is extremely well made and very thin.  Even the edges are still sharp!  It is made of a dark blue-black flint most likely from Coshocton County, Ohio.  This artifact was either a butchering knife or perhaps a spear point.

An even rarer artifact is a stone adze found in the upper midden layer in unit 498N 512E.  It is a complete, undamaged specimen of a wood-working tool that was carefully ground and polished from a very attractive variety of igneous rock called porphyry.  In the image below, the distinctive crystals of feldspar, called phenocrysts, can be distinctly seen.  This tool was most likely made from a glacial cobble found in French Creek or another local stream. The discovery of an undamaged tool like this seems unusual in a refuse context such as a midden.  Perhaps this particular stratum is more significant than we first assumed. 

Next door in the adjoining excavation unit, a hard day of plow zone excavation resulted in the complete exposure of the midden deposit.  At first glance, it looks something like an asphalt pavement--and is nearly as hard to dig--but on closer inspection dense concentrations of charcoal, burned soil, burned bone, flint flakes can be seen between the large chunks of fire-cracked rock.  Shown below is a view of the midden floor at the end of the day.  This floor has not seen the light of day for some four thousand years!  And much more undoubtedly lies beneath.

Monday, June 16, 2014

CMNH Field School Returns to the Field

After a one year hiatus, the CMNH field school program is back in business.  After five successful seasons at the Heckelman site, we have returned to Burrell Orchard, where we worked in 2008.  This site is one of the most unique archaeological localities in northern Ohio.  It contains a dense accumulation of midden (refuse) and other features that date to the Late Archaic period, about 4000 years ago.   In 2008 we located and sampled the midden deposits and found a number of cooking pits and smudge pits used for smoking deer hides.  This season we will continue to excavate more of the midden deposits near the old orchard, but also carry out a systematic shovel-test survey of the remainder of the site.   To read the report of our 2008 work, use this link.

Today we began our shovel-test survey.  Things started out slowly, because we had to clear survey transects in the tall weeds and grass that cover the field.  Luckily we had some willing grass cutters in Michelle N., Char S., and Marcia R.  Here you can see Char's mowing technique.

Four shovel-test units were laid out on the N490 transect. Each unit is 50cm by 50cm in size and is excavated into the midden deposits and ends at the artifact-free subsoil.  Each crew discovered flint flakes and fire-cracked rock (FCR) in almost every unit.   Below the 25cm-thick plow zone, we found the dark, organic midden deposits containing more flakes, FCR, bits of charcoal, and some burned bone.  Only a few pieces of historic material, such as window glass, were found, suggesting that this was not a heavily used area of the Burrell family farm. The most significant find of the day was the discovery of the base of the lanceolate projectile point shown below.

These long flint knives and spear points were used by the Late Archaic inhabitants of the site for hunting and butchering deer and other animals.  We often find only the broken bases of these points, which tells us that re-tooling--the discarding of broken point bases and re-hafting of new points--was a common occurrence at this Late Archaic base camp.   We will continue our shovel-testing tomorrow and in the coming weeks in order to get a better picture of what lies below the surface of this large settlement.