This week's blog contribution comes from Autumn Williamson, Jason Hines, and Blake Davenport. Enjoy!
Last Friday we had a couple of
visitors… several hundred, to be more precise. The local middle schools visited
for CSI, or Cultural Scene Investigation Day. The students visited several
different stations where they learned about the work done at the site and the
lifestyles of the people who once inhabited it. Jeremy and Erica told the
students at our station about the work that was done last year and our current
excavation process, as well as some artifacts such as pottery found during
previous excavations. Ed Herman, IU graduate student and Prehistory Research
Fellow at the GBL, also talked about flint napping and gave an atlatl throwing
demonstration. Matt Pike of IUPUI gave a presentation about magnetometry, and
Jasmine, also of IUPUI, told the students about water screening and the cool
things we’ve found. Most prominent were a bone needle, which was used to sew
clothing, and a shaft straightener, which allowed shafts for atlatl darts or
arrows to be cleaned and straightened.
Ed Herman is a flint napper and PhD
candidate at Indiana University Bloomington who came and gave a lecture on
stone tools and flint napping on Thursday; he also stuck around to speak with
the kiddos at CSI days on Friday. He is
a very skilled flint napper who exceeds at fluting as well as notching
points. Fluting is driving a final
longitudinal scar from the base to the tip of the projectile point and notching
is removing material from the rock in order to haft the point onto a
shaft. We found a point while water
screening, which Jeremy said was a Levanah point, and described it as being in
the shape of an isosceles triangle. He also mentioned that a Madison point is
in the shape of an equilateral triangle, hence the mnemonic “Levanah Isosceles
Madison Equilateral,” or LIME, that is used to remember the difference between
the two points. The primary material
used by Mississippian peoples (who inhabited this site) was chert. There are many different types of chert such
as Texas Perinalis, Burlington, Keokock, and Ohio – just to name a few. Chert is a type of rock that will break
predictably when struck percussively or flakes with pressure. When producing a projectile point flakes are
broken off and these are what we find most often when excavating. The basic parts of a flake are a bulb of
percussion which occurs at a right angle to the platform, compression waves
(like ripples in a pond) moving away from the bulb of percussion and radial
fissures, with the whole flake being in the shape of a clam shell.
Now
that we are into our second week of excavations here at Angel Mounds we are all
starting to get comfortable with our work and are through the disturbed plow
zone into the actual cultural stratigraphy and features of the site. In archaeology, stratigraphy is the verticle
layering of archaeological material through time used to tell when events
happened in relation to each other. Features
are identified by soil changes, such as texture and color, and indicate an
event in time. All organic material decomposes
through time, changing soil to look different from the surrounding soil or
matrix. Some features that we have found
are a yellow color sand line that has been interpreted as a possible wall
trench (a line that was dug out of the ground with a hoe in order to construct
a wall in its place), a wide line of gray clay that has been interpreted as the
palisade trench that surrounded the village, and a very dark brown circle that
is interpreted as having been a post hole for building walls. We have a lot of artifacts that come out of
the ground and go through water screening, such as pottery, flakes from flint napping,
projectile points, and faunal (animal) bones.
These are interesting and will be catalogued in order to aid in the interpretation
of the site but are actually not our main concern in excavation as one might
believe. We are more interested in the stratigraphy
and features because they provide information about chronology and activities
at the site.
Tim
Schilling, who is a Research Postdoc at the GBL, gave a lecture this week on
the chronology of the Angel Mounds site as well as the broader Mississippian
culture. He discussed how archaeologists
use the principles developed by geologists to determine the chronology of
features, and therefore activities, in excavations. For example:
if feature A is found above feature B, it is reasoned that feature A must
have occurred later than B. He also
discussed the change in perception of chronology and methods used to determine
it. The first chronological assessment
of Angel Mounds was done by Sheri Hilgeman who used pottery and radio-carbon
dating to create chronology of the site.
She also compared pottery found at Angel Mounds with that of the same
style found at other Mississippian sites.
Newer methods do not rely on material culture from sites to create a
chronological sequence since stylistic differences vary so greatly through time
from one site to the next.
Dr. Bill
Monaghan of the GBL and Matt Pike have also been on site recently in order to
survey and set points which create grids around the site. The students have been lucky enough to be
invited in groups of two to help and learn how to survey using the total
station. This is a very expensive piece
of equipment that uses geometry to create points, or specific locations at the
site, in space based on an x, y, and z coordinate system. We set the location of the machine in
relation to known points that have been plotted in previous years; then the
total station uses that information to “shoot in” new points that we know the
coordinates for but cannot locate by ourselves.
When we find the new point a stake is driven into the ground so that we
can find it again without using the total station. The points that we are marking this season
are being used to make up 30 meter by 30 meter squares where Matt Pike is going
to use magnetometry, a method that measures magnetic signatures of the ground
and can be used to locate features. To
do this he first lays out lines along the north and south borders of the 30 by
30 meter squares. Then has two helpers
move a third line, which is positioned perpendicular to the north and south
lines, as he walks along it back and forth with a magnetic gradiometer. The magnetic gradiometer registers the
magnetic signature of the ground that he walks over and when he is done with a
grid he hooks it up to the computer which shows him this signature in picture
form. From this picture we can see the
soil differences that we look for when digging and it gives us a better idea of
what is under the ground from the past as well as ideas for future digging
spots. This method is significant
because it is non-destructive but allows us to identify underground features,
such as the palisade trench.
Here are just a few pictures from this weeks work :)
Get by with a little help my my friends clean scraping the plowzone!
Students Arron Williamson and Gary Macagaeg shown here.
Ed Herrmann, a Prehistory Research Fellow from the GBL, showing
students an atlatl.
Again, Ed Herrmann instructing the students on different types of lithic (stone tool)
materials and forms.
Field school instructors Jeremy Willson, Matt Pike, Bill Monaghan, and Tony Krus
litsening intently to Ed's discussion.
Bianaca Brammer examining a very sharp obsidian flake.
Ed Herrmann demonstrating how to flint napp stone tools
A view from above as Ed continues to flint napp surrounded by examples
of stone tools and interested students.
Students examining Ed's creations.
Visiting lecturer Dr. Timothy Schilling who talked about chronology at the Angel site.
Tony Krus discussing paperwork with Corinne Schultz.
Karin Williams carefully brushing soil off of a concentration of deer
remains including a mandible (which got its teeth bushed!), scapula, and
several long bones. The bones exhibited evidence of human processing.
Students excavating in the southern half of the unit 12-E.
Gary Macadaeg cleaning excavated soil using a dust pan. The soil is then
transfered to a labeled bucket for water screening.
Busy as a beehive!
Sometimes we all need a little boost.
Karin Williams and Hannah Boes shown here nest to a partially excavated
wall trench. We have bisected the wall trench in order to see its profile and
composition from the west.
Instructors and students discussion texture changes in soil
in order to determine the borders of a feature.
Jeremy, Tony, and Tim discussion features and soil zones in the
western half of the unit.
Lela Grant emptying her dust pan full of dirt smiling all the way.
Tim Schilling examining the multiple wall trenches interpreted
as multiple rebuilds of a single structure.
Jasmine McClure the photographer!
Excavations in the western half of the unit. This area is just inside the
palisade trench and includes the wall trenches of a structure as well
as several other features.
Bianaca Brammer and Blake Davenport rocking the dirt.
Karin Willaims clean scraping the norther wall of her 1x1. This keeps
the following levels from deviating from the one square meter borders.
Hannah Bose arm deep in the northwestern corner of a wall trench.
Corinne Schultz excavating a VERY deep pit at the western side of the unit.
This is why we call her Auger.
Auger examining an artifact from her never ending pit.
Tony Krus even donned a had lamp (thanks for Gary) in order to examine
the deep feature.
Stay tuned for next week!!!
