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'" UTAH ARCHEOLOGY A Newsletter Vol. 3, No.2
June 1957 Contents
Editor's Notes . . The Recognition of Archeological Sites How Old Is It?
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. . . • • Lloyd Pierson 3
. . James, H.
GUnnerson
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Pictograph located about 40 miles southeast of Escalante, Utah. Recorded by the Univ. of Utah Glen Canyon Archeological Survey. Utah Archeology is distributed quarterly to members of the Utah Statewide Archeological Society. All correspondence should be directed to the Editor-James H. Gunnerson, Department of Anthropology, University of Utah, Salt Lake City 12, Utah.
Editor's Notes M,eeting From the response to the questionnaire re'garding a state meeting of the society, it is obvious that summer is 'not the best time. Very few of the sheets were returned. An attempt will be made again in' the fall to set a date for an organizational meeting of the society. Summer Activities The University of Utah has fielded its first party in the Glen~Ganyon area. A small contract from the National Park Service made possible the hiring of Dr. Robert H. Lister of the University 'of Colorado as" Field Supervisor, along with a four man crew. Prospects are-goo4 for getting additional funds after the first of July for continued and increased salvage activities in the area. Plans for other field work are still in a state of flux, pending field school response (which at the moment appears to be too light to justify holding the field school) and developments in salvage activities. By the time this ',ae~S1e..t ter reaches you, the University of California field school will probably be at work at Paragonah. The party will be living in dormitories on the College of Southern Utah campus at Cedar City. Conferences The Pecos Conference for southwestern archeology will be held at Globe, Arizona, on August 29, 30 and 31. The Great Basin Archeological Conference will be held at San Francisco State College, 1600 Holloway Avenue, San Francisco, California, on August 26 and 27. Members of the USAS are welcome to attend either or both of these conferences. - Publications Papers o f the Third Great Basin Archeological Conference by Fay-Cooper Cole and others, University of Utah Anthropological Papers Number 26 has recently been published by the University of Utah Press, Salt Lake City, Utah. It can be purchased fr'om the press. Price $1. 500 Two other University of Utah Anthropological Papers dealing with Utah archeology are in press. Number 27 will be Danger Cave by Jesse D. Jennings, which is the final report of work done by the University of Utah at this important site near Wendover, Utah. Number 28 will be An Archeological Survey of the Fremont Area by James H. Gunnerson. It is a report of three years of work in northeastern Utah by the Utah Statewide Archeological Survey. Moab Chap ter Your editor had the pleasure of meeting with and talking to the Moab Chapter of the USAS on April 18. Museum Th~ UniversitY ,of Utah Museum of Anthropology has gone onto its summer schedule and is open 9:00 a.m. to 4:00 p.m, Monday through Friday. Vis}tors are welco~e.
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This Issue Lloyd Pierson, the ' author of the article below on recognition of' archeological sites, is on the staff of the National Park Service at Arches National Monument. He has had extensive training in archeology at the University of New Mexico and is active in the Moa,b Chapter of the USAS. The other article is by your editor, who needs no introduction. i
THE RECOGNITION OF ARCHAEOLOGICAL SITES Lloyd Pierson Man is and . ba~ ~een: throughout his history an inveterate ."litterbug ., H Wherever he ' has spent any length 'of time he has left litter ~ garbage, fallen buildings, broken tools ,and utensils and even some of his fellow beings in the form .of burials. These are the things that make up ' . archa~ology, however, and lead uS to an insight into the life and times of the group whose remains are under study. j
The locating and recognizing of areas that may be classified as , archaeological sites is at times difficult. There are however a number of time proven aids or clues to finding archaeological sites. Some . of the ' mos~ useful (and relevant to Utah ) ar~ thasa: j
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Standing wai t s.: Th,e se are obvi ously man I s handit.,o1-"k and deno t e rel at:;tyely J. ~ngthy period of occupat ion by hj.m. He ight of wall in an open site is often i ndicat i ve :bf either size or age .. Much wall still standing may imply either a larg~ ruinl or a [recent one'.
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Potsherds: An aoundance of broken pottery is a definite clue to the location of sites. The po t sherds may ,occur dn the site proper j ~n t~~' f ~!I 4~h heap uStia,l iy associa,t ed with m6~t si~c:~ ;~: or.:Ln mat~~ial ~a~hed :E om i eith~r the site the trash heap. Pottery l.S undoubt~dly one , of t e most durable of thl.ngs produced by man and hence extremely l:l'sef~1 . in locat~ng his occupat ion sites. Unfortunately not all 'peoples made pottery. '
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Vegetation: H~an occupation of a small area appears to alter the composition Qf the soil of that place. This change is due to the materials unintentionally added to the soil, such ,as ash, vegetable material, bones, etc., by the people living there. The additions enrich the soil making a noticeably lusher vegetation cover on the site than on the surrounding area. This difference is particularly noticeable from the air either with the naked eye or on aeri~l photos. Aerial observation for sites is best in early morning or late afternoon when shadows from low mounds or depressions accentuate the vege t: ation differences arid aid greatly 'in site discoverie~.
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¡Land Forms: Nature seldom produces geometriciorms while man frequently does. Geometrical figures such -as cLrcular anq,::-ectangular depressions an.d mounds, usually prove, upon inspectinn to be man made.¡ Particular 1types of landf~ms are often preferred as living sites by certain groups. In Some - areas steep-sided -hills were desired, in others low mounds, caves or overhangs were chosen. As one becomes increasingly familiar with the habits of the prehistoric inhabitants of an area it becomes easier to predetermine possible site locations and to find them. 5. Trash: Accumulations of charcoal, burned stone, flaked stone, wo,r ked -bone, --work~d shell artifacts a.nd -- r~fuse bone, -wh~n - found in some q.uantity may le-ad to the location of asi-te ei-t her diz:ec't ly or through¡ an associated trash pile. A favorite place in -the Southwest to look for charcoal and other trash is in the banks of arroy~s or in road cuts. Many early man s~tes haye been found in this manner. 6. Building Stone: A great quantity of stone suitable for building purposes and occuring in consistently sized blocks.. n,o t natural to the area serves as another criterion helpful in locating sites. 7. Caves: Qpe of man's favorite habitations is the cave. Frequently he built "cliff dwellings" in them. Many caves were lived without benefit of any t'}l.p e of building in them. A good indication of a "used" cave is smoke on the ceiling or - the presence of human trash -either in the cave or in front of the cave. 8. Pictographs and Petroglyphs: These are considered by most archaeologists as worthy of site designation in themselves. They are also frequently in direct association or not too far distant from a habitation site of some sort. 9. Springs, Waterholes, etc.: Man must have water and in the arid Southwest any source of water was an ideal locale for him. In general one will find that sites preferred by prehistoric man are the same that would be preferred today by farming or hunting and gathering peoples. However, one must keep in mind the possibilities of changes in climate and landfrom in the past that would have led man to utilize what would now be considered as undesirable locations.
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HOW OLD TS IT? James H. Gunnerson One of the questions most often asked of the archeologist is "How old is it?" and this is followed by "How do you know?" Not only is the age of archeological sites and finds of interest to the average layman, but it is also of great importance to the archeologist when he is interpreting the new material and trying to solve the related problems. Fortunately the archeologist has at hi~ disposal a number of methods for determining the age of his finds. These methods can be grouped in two categories: methods for ~stab\ lishing relative chronology and methods for determining absolu~e chronology. All methods are useful and it is not possible to indiaa~e one or t~ other as most important. Each method has its appli- cation and lim~tations and many require the assistance of specialists in other fields to carry out the technical procedures . MethodS of the first category, that of establishing relative ages of two or more phenomena, simply determine which is the older but do n~t tell how many years or centuries old either is. The most impQ~tant datipg method of this category is stratigraphy, which was us~d in geology before it was applied to archeological material. Th~ principle Qf stratigraphy is actually quite simple--where one finds' layered (jeposits of cultural material such as in a cave or in a trash deposi~, the lower layers must ~ave been laid down before th~ ' qpper laye~s, and hence are older. In many cases the stratigraphy of an archeological site can be difficult to int~~ret.The archeologist must always watch for evidence of ~isttrl;:bances-. - FO'r-- <*arrtp'i~i a " ho-le~.may=have--li>een- dug- ,ifl.t&.. ~e14路 tayer and the dirt from the hole p1led or spread upon the surface 9f t;he deposit. This would put a layer of old ,material on top of qiore ' r~cent- material ~ There _is always the poss;i.bility of older : . _ tl\aterial being included in a more路 recent strat~ . _~ :: The converse, that of having recent material in an old deposit, is not' possible unl~ss it has been introduc~d through a rodent or other hole. One safe iule, therefore, is that a stratum can The no older than the most recent material where there has been no intrusion. Stratigraphic ~vidence is especially ~seful where various' occupation levels are aeparated or sealedoff路by sterile deposits ,such as -sand or caliche or whet-e several structureshave :-been built Lone on tBp of another. I
For the most part, dating by stratigraphy is restricted to use w~~hin single 路 sites and the Establishing of sequence of different sites ~sually requires other dating methods. However, if an archeological ~ite is in one of a stratigraphic series of identifiable geological deposits, its age relative to other sites situated in the same
g~ological series put at a different location can be established.
One ingenious method of establishing relative chronology is called seriation. It is possible to establish the sequence of culturally r~lated archeological sites where there , are large enough samples of $everal different artifact types which have limited duration in timen T~ accomplish th~s, the percentage of each type at each site is calculated. The sites are then ordered in such ~ manner that the perc~ntages for each type show a smooth increase or decrease. This method assumes that types of a~tifacts will show the same p~ttern of increase and decrease at ~ll sites in a limited geographical area which is homogeneous culturally. If the samples ar~ adequa~e, ~pen it is possible to align the sites in chronological order, but i~ is then necessary to establish which is the oldest end and which is the most recent end of the series by some other dating method. ;~
One chemical method for. determining relative age of bone has received c~nsiderable attention recently. This method is based on the fact toat bone will gradually absorb fluorine from ground water. The actual amount of fluorine 4bsorbed will vary from place to place which restricts the application of this\ method to a single locat i on. The amount of fluorine is determined in each of two specimens of bone which have been found together to determine whether or not they are of the same age. If the fluorine content is the same, the age is the same. Th,e use of this fluorin~ analysis is especially useful when one or a few human bones are found apparently associated with one or a few bones of animals which are good index fossils and there is doubt as to whether the two were coexistent or whether the bones were redeposited from different sources. Fluorine analysis was used to es~ablish that the mandible and skull fragments of Piltdown man were no~ of the same age. first successful absolute dating of prehistoric sites was made possible through the study of tree rings. Many trees grow by adding on~ growth ring per year. These rings can be seen in the cross sections of the logs or limbs. The width of the rings reflects the climatic conditions.; especially rainfall, for thE! year. Since climate tends to be the same over limited areas, the grclwth pa/tterns for trees living at the same time in an area will bE! the same. Thus it has been possible to set up a chart starting at the present with freshly-cut trees to show the variations for each year that the tree grew. The charts have been extended back by finding trees which w~re cut down a few years after the recent trees sprouted and m~ tching the outer part of th~ pattern of the older tree with the inner part of the pattern of the recent tree. By matching the growth Th~
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patterns on the outer rings of even older specimens with the inner rings of the more recent ones it has been possible to extend the.· dendrochronological master char.t for the south~estern -United States back to about 50 years B.C. The chart has bee~ checked and strengthened by numerous samples for the'ent~re period. There are several precautions which must be taken ·in dealing with treie ring dating. Not all species of tt-ees are equally good ii.ndica- , tors of climate change, hence samples need be r~stricted- to spet:ies that are . Also, some individual tre,es, suc·h as those which .-grew near permanent water, would not reflect the climCjltic changes so~heY 'would . not -match the master chart. One -w ould not know until the s~mplE;!s were checked in the laboratory that such a specimen would be unuE?abl~. Another chance for error is that some timbers were reused a long -time after they were cut and first used. The tree ring date tells you only when the tree was cut o.r stopped living. Thus it is important that several separate timbers be sampled to be certain of a true date for the construction of a structure . Where dating is carried out ·on charred wood from fires, the outside or bark date is often not ascertainable, since an unknown number of outer rings would have been burned off. Thus all dendrochronological dates would be · minimum dates--that is, they tell you that a site was occupied sometime after a given date, the most recent one found at the site. Usually, dendrochronological dates will be secured from several different samples at each site. Where the bark dates for several of these cluster around one date, it is safe to assume that the site was being occupied at that date. The problem of selecting specimens which are definitely associated with the cultural manifestation to be dated is the ' responsibility of the archeologist. )
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In recent years 9 the dating method which has attracted the most attention is the Carbon 14 method. It is possible to determine how long ago any plant or animal material was part of a living organism if that organism was alive in the last 35,000 years or so. Dating is possible because there is a known ratio\: between the rare Carbon 14 and common Carbon 12 in all living organisms. The Carbon 14 decomposes at a known rate and the Carbon 12 does not change. By . measuring the amounts of each of these isotopes of carbon in a piece of charcoal from a camp fire, or in a wooden tool or inl a bone of an animal eaten, it is possible to determine when the associated people were living'. Decomposition of the radioactive isotopes is measured in half-lifes--that for Carbon 14 being about 5568 years. Thus if a sample or organic material from an archeological site has only half as much Carbon 14 for the amount of Carbon 12 present as would be found in living material, the sample and hence the site would be about 5568 years old. If the sample had only one fourth as much Cat:bon 14 ('as is found in living material, it would be about 11,136 years old.
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One '. big problem in dating arche<;>logical sites by the use of Carbon 14 is that of contamination of the sample of organic material to be analyzed . If more recent organic material has become mixed with the sample 3 the calculated age would be too recent . Contamination can result from such sources as small roots growing into the sample or organic material being carried into and deposited in the sample in ground water . Contamination must be avoided after the sample has been taken from the ground and can be prevented by sealing the sample at once in a clean glass jar ~ It is up to the archeologist to collect the samples which he does not suspect of being contaminated and to h~ndle them in such a manner as to prevent their becoming contaminated. It is also his responsibility to collect samples which will actually date the cultural manifestation the age of which is in question . Various materials differ in their desirability for analysis , both in the chance of contamination and in the amount of carbon as compared with the size of the sample. Wood charcoal is generally considered the best m~terial. Following this in roughly decreasing order would be uncharred wood and plant material , dung , charred bone 3 uncharred bone and shell. Work has also been done with such materials as peat and finely divided organic material in soil . Material from dry caves is preferable to that from sites exposed to moisture. Dates derived:- from Carboni 14 analysis are usually given with a plus or minus figure after them . This amount is arrived at on the basis of prpbable error in the laboratory procedure and means that the actual )proportion of Carbon 12 to Carbon l4>.iri. '2 sample has the probability of about two to one of indicating an age withi n this range . This indicated var i ation does not reflect the possib le err ors in t roduced by contamination or the probability that the sample actually dates t he cultural manifestation . The -necessity of giving a range of probable dates for a sampl e instead of an exact date can never be eliminated , s i nce the disintegration of Carbon 14 atoms, which is actually the thing measured, c onsis t s of random events and must be calculated over a peripd of time. Prolonged age but this is ,. . counting would narrow th~"_ range of the probable , .. not ' cons~dered practical, for the analysis is costly 'and variable~ such as contamination can not be completely controlled . A date with a plus or minus ten percent or so variation is very useful to arch~ 010gists and has provided a wonderful method for dating many sites not previously datable. The accuracy of the dating is still not universally accepted , but continuing work will eventually establish the reliabilit y and limitations of the method . .
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The use of written records to determine the age of archeological sites is useful wherever this method is applicable. Correlation of material found in the ground and the all-too-often vague descriptions and locations given in written records is often difficult and uncertain. It is sometimes possible to identify a particular archeological site as one described in accounts of t~avelers, in which case the archeological work takes on a great deal more significance. In other instances, the archeologist can identify a site as being of a type reported in historical documents at a particular date. Archeological sites of cultures which had writing can often be dated by inscriptions on munuments or buildings uncovered~ The main problems encountered are the translation of the language'an~ the correlation of the calendrical system with ours. One must a1sope certain that ,the inscribed dates are those of the time of construction rather than dates of some past event which is being commemorated. Associated artifacts which bear dates, such as coins, or artifacts for which there is documentation as to the date of manufacture, such as guns or dishes, form a special class of index artifacts which have their closest affiliations with written documentation. Where such artifacts are numerous and represent a short time span, a reasonably accurate date can be assigned to the site. Where such artifacts are vey rare, it is possible that the represent old pieces which have been saved, perhaps heirlooms. One can be ~afe in assuming that occupation of the site is more recent than, or as recent as the most recent artifact. Frequently, archeological sites are dated by secondary correlations. The most useful of such methods is dating by means of index artifacts or index fossils. If the age, either relative or absolute, can be established for some particular artifact or fossil, and if the duration through time of the fossil or artifact can be demonstrated as short, then it is possible to assign a like date to sites where the artifact or fossil is found. For example, it is often possible to determine at one or a few sites the period that a particular type of pottery was made. If the same type of pottery is found at other sites, th~se sites can be assigned, with reasonable certainty, the date of the pottery type. An extension of this method can be applied to ",artifacts or fossils which have longer duration in time but which have a definite date of introduction or extinction. Where such a date 1's established, then it is possible to date a site containing such artifacts or fossils as after or prior to the date as the case may be.
10 Dates or ages can also be established for archeological finds by correlation with geological phenomena l The most frequent correlations are probably with terraces~ either river~ lake or marine ~ which have been dated. When a site is within a particular terrace fill, it is of the same age as the terrace; when it is on top of a terrace~ it can be said to be more recent than the terrace. Some sites have been covered with volcanic ash or lava from known volcanoeso Where the eruption can be dated~ a terminal or minimal date is established for the sites covered In other cases 9 relative dating is possible where one site is above the deposit and another is below ito , 0
There are many other methods of dating archeological matetial which are useful in specific cases o Several of theseJ.re based ,on cor~ relations with changes in climate which have been dated either relatively or absQlutelyo For example 9 occupation of sites has been ' correlated with changes in the level of rivers J lakes or seas~ and with climatic changes as evidenced by the bones of animals and by pollen or plants which are restricted to particular climates or with mineral deposits,which could have taken place only under certain conditions . Some' apparently workable methods of dating are actually very ; pooro For example , a site deeply buried is not necessarily very old, since many . feet of dirt can be washed or blown into an' area in a few years. Sit~s 'ÂŁÂŁ tOE of old terraces or on old shore, lines ~re not necessarily as old as the terrace or shore lineo Degree of decay or decompo~ Sition is not a good indicator of age, since the rate of these processes varies greatly with different conditions 0
In brief, the archeologist has to be constantly on the aler~ for that will tell him how old his finds are s and he must choose tr0m among many possible methods, those which will be useful in the dating of each particular site o
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Utah Archeology Department of Anthropology University of Utah Salt Lake City, Utah
Non-profit Org.
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