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Soils descriptionIntroductionReading the soil is a critical
skill for any archaeologist. Often subtle differences in colour,
texture, and compositican provide critically important information
about different types of deposits. It is imperative to apply the
same of criteria and categorizations to soil descriptions rather
than relying solely upon subjective terms and impressionSoil
Colour:Soil colour is determined through using the Munsell system
of colour notation. A range of Munsell colour charts bound in a
vinyl covered notebook which should be treated gently and used for
filling out the soils description the context sheets. Colours are
read through comparison with the colour chips in the notebook. In
transcribing t
colour notation, record the page number (e.g. 10YR) and then the
chroma (listed on the row along the side of tpage) over the hue
(listed along the bottom of the page), e.g. 10YR3/4.Be sure to:
measure all colour in adequate daylight- in shade, not in direct
sunlightrecord the colour from moist soil from a freshly cleaned
area
if the soil colour is not uniform, also record the shades of the
mottlingSoil typeThe general texture of a soil is determined by the
relative proportion of particles of different sizes which make the
soil. The particles range in size from gravel to sand to silt to
clay. Generally, the texture of a soil can determined by working a
small, moist sample with the fingers.Soil size grades:Sand: Loose
and clean-grained material with particles that are visible to the
naked eye. Particles easily felt betwethe fingers.Silt: Particles
are too small to be seen with the naked eye and cannot be detected
individually with the fingers. Srubbed between the fingers feels
silky.Clay: Particles are too small to be seen or felt. When moist,
clay is sticky, cohesive and plastic.Common particle
combinations:Loam: feels gritty in the hand but has a reasonably
smooth texture and is rather plastic. The moist sediment will foa
good cast and is composed of nearly equal parts of silt and sand,
with about half their amounts of claySandy loam: contains mostly
sand but has enough silt and clay to make it cohesive. Will form a
cast when moist, bthe cast is easily broken. A true sandy loam
contains 50% sand, 30% silt, and 20% clay.Silty loam: has a
slightly silky feel and forms clods when dry. The lumps are easily
broken and the resulting materfeels rather soft and floury.
Contains at least 50% sand and silt together with about 12-25%
clay.Clay loam: Fine textured deposit which readily breaks into
clods or lumps that are hard when dry. Moist sedimenplastic and
cohesive, containing nearly equal amounts of sand and clay.Soil
texture and coherence:The way that individual grains in a soil are
held together is known as coherence. For loamy, silty, or clayey
soil, taa sample of moist soil between the thumb and forefinger and
apply pressure. For sands, observe the average sizeparticles.Loams,
silt, and clay:Silty: crumbles under light pressureFriable:
crumbles under moderate pressureSticky: sticks to the fingers and
barely crumblesPlastic: does not crumble at all, more like Play-Doh
(!) in texture
Sands range from granular (composed of extremely small
particles) to gravelly (composed of particles over 2mmdiametre).
Fine, medium, and coarse are acceptable descriptions.InclusionsAny
element forming less than 10% should be referred to as an
inclusion. A chart for determining percentagesoutlined below.
43Chart to assist in the determination of soil type. 44Chart to
assist in determining percentages of inclusions. 45Describing
cutsShape in plan: Describe the shape in plan: circular, oval,
square, rectangular, sub-rectangular, kidney-shapregular or
irregular.
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Corners: Are the corners rounded or angular?Profile:
U-shaped/Vshaped/etcBase: Is it even or uneven? Is it pointed or
flat? If it is a stakehole try to discern the shape of the wood.
Chipoint/pencil point/flat bottomedOrientation: Is there a
difference between the width and length of the featureis it a
linear feature, give the orientation. If it is a posthole or
stakehole, give the relationship between the base atop.Truncated
by: Is it truncated by a later feature? If so, what? Can you
discern or postulate on the original shape?Break of slope top:
Sharp/Gradual/Not PerceptibleSlope: Vertical/Steep/Gently
sloping
Break of slope base: Sharp/Gradual/Not perceptible.Inclination
of axis: If it is a stakehole or posthole, which direction and at
what angle does it project? This informatiis directly related to
extrapolating the shape of a superstructure.Describing
structureForm: Is it a wall, drain, foundation, repair, etc?Size of
material: Note the size and range of the material.Number of
courses: How many courses make up the context?Finish: Is it
finished/faced roughly, with regular coursing, with cut stone, with
roughly cut stone or Ashlar.Material: Is it built of stone, bricks,
block, etc?Tool Marks: Are there any local tool marks evident on
the construction material?Bonding: Has any bonding material been
used in the construction. Describe it.
Faces: How many faces does it have and which directions do they
face?Rendering: Is there any rendering material? Describe
it.Archaeological PhotographyPhotographs represent an essential
element of any site archive, and also serve as the principal means
of conveyithe practice and results of any excavation to the public.
Record shots are taken of each archaeological contewhile working
shots are taken systematically during the course of the
excavation.Preparing for record shots is a time-consuming but
absolutely necessary process. All visible surfaces should carefully
trowelled to ensure maximum visibility of features and interfaces.
Roots should be clipped, and masonand stones brushed. All
extraneous material should be out of the photograph, for example
Coke cans, wellclipboards, pencils, gloves, hats, brushes, buckets
trowels and other peoples feet!Every photograph should have a scale
and a north arrow. The first image taken on each camera should also
inclua menu board to identify the site, unit, context, direction,
and date. The board and the north arrow should be placparallel to
the camera view. All photographs are recorded in the Photo Log
book.Photographs will be taken employing black and white film,
colour slide film, and digital file. Cameras should handled
carefully and with clean hands only!!Drawing contexts in plan and
in section:Plan drawings are measured recordings of a context or
contexts viewed from above. Generally, contexts are plannat a scale
of 1:20 following a set of standard drawing conventions. All plan
drawings receive a unique drawinumber assigned by the drawings
technician or another member of staff. It is imperative that
information about context, recorder, date and plan number are
recorded on a label which is placed on the drawing. All measured
pand section drawings are made on drawing film, which is placed on
a drawing board over lined graph paper. Wha field drawing is
complete, it is removed from the board and carefully rolled up. All
drawings will beinked-inthe laboratory for permanent archival
storage and publication. 47
Section and elevation drawings will be made of any sectioned
feature, the edges of excavation areas, aarchitectural features
such as walls. The appropriate scale used will depend upon the size
of the section; howevall feature drawings should be produced at
1:10. Again, please use standard drawing conventions as
illustrated.When writing a title block, please follow the relevant
order outlined below. The title block should be written in ttop
left hand corner of the sheet in block letters) e.g. c.2-3mm high).
The plan and section number should duplicated in larger print
(c.10mm high), in the top right-hand corner. Please, try to write
legibly and remember thoften what you are creating a record of will
be destroyed.
