Abstract:
An archaeological sifting basket is disclosed for use at the site of an archaeological dig, said basket comprising a frame, with wire mesh screen attached. The basket is hinged to be collapsible and has a bottom wall made up of two planar areas arranged at an angle to each other for increased flexibility of use.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The basic unit of archaeological exploration is the site, which has been defined as &#34;any location which exhibits evidence of past human activity.&#34; The definition is purposefully vague so as to encompass every conceivable area which may prove useful to research, from a campsite which may contain only a few artifacts to a city of several hundred thousand people. 
     Sites are located by their unique characteristics, stone tools, or pottery fragments lying on the surface, vegetation differing from the immediately surrounding area which indicates that the site may have been cleared in prehistoric times, or suspicious looking mounds or depressions of regular form, which may have been man-made. Sites may also be located by exploration of areas which experience has indicated were most frequently occupied, river forks, the edge of a bluff overlooking a river valley, or a natural stone formation providing shelter. 
     Once the site is located, the archaeologist normally makes out a survey form, systematically recording the location of the site on a map and describing its features. Normally, the site is photographed and a sketch map drawn. The site is given a number for identification, which is used on all notes or materials obtained. 
     After all the sites in an area have been surveyed and the survey notes reviewed in detail, the archaeologist determines which sites to excavate, based on his own particular interests and the reason for his research. 
     A major purpose of excavation is to determine the specific location of individual objects recovered from the site. Horizontal location may indicate that certain areas of a site were set aside for tool making, cooking, or keeping or slaughtering animals. By knowing the exact horizontal location of objects received, the plan of a camp or village may be reconstructed and much insight as to the lifestyle of the inhabitants is provided. Vertical placement or stratigraphy, may indicate the presence of several different groups of people living on a given site at different times. 
     Horizontal placement is normally determined by use of a grid system of N-S, E-W lines dividing the surface of the site into a pattern of squares of equal area. The site is then sampled to determine the most desirable squares for excavating. A common method of sampling is digging test trenches at right angles to one another in an X, L or T shape. Squares determined to be most likely to be productive are then excavated one or one/half at a time. 
     Vertical placement is normally measured from the surface or from an arbitrary datum level. Each object located is carefully recorded, along with its horizontal and vertical placement. 
     2. Prior Art 
     Actual excavation is frequently done by means of a trowel or scoop. Earth is transferred to a bucket and then to a sifter for the recovery of artifacts. 
     Conventional archaeological sifting devices comprise a wooden frame forming shallow box structure having wire mesh attached as a floor. The frame is normally of such dimension and weight as to require that it be supported on legs and spaced at some distance from the dig site. This arrangment requires the archaeologist to transport buckets of earth from the dig site to the sifter, utilize the sifter, and return to the dig site for more earth. 
     The conventional sifter has disadvantages in that time and energy are expended in continually transporting earth to the sifter, waiting for others to finish using the sifter, and returning to the dig site. 
     In addition, as explained, an accurate determination of the placement of objects located is essential to the research of an archaeologist. Accurate placement is extremely difficult to determine when earth is sifted in large quantities as it tends to be when the sifter is some distance away. Disposal of waste material which accumulates beneath the conventional sifter is yet another disadvatage. The sifter must be positioned prior to commencement of excavation. During excavation, however, archaeologists may discover, from the artifacts found, that there is need for further exploration precisely in the area occupied by the sifter. 
     The article PARTIAL RECOVERY, AND SAMPLE BIAS: THE RESULTS OF SOME SIEVING EXPERIMENTS, by Sebastian Payne, taken from the book Papers In Economic Prehistory, E. S. Higgs, Cambridge University Press, describes several alternatives to the conventional sifter described above. 
     One of these is the throwscreen, a mesh, set nearly upright, against which the earth is thrown. Larger particles roll down the near side to the ground and are searched through. The throwscreen is commonly used but is generally considered inefficient and difficult to work with. 
     Common hand-held sieves are soemwhat better, but have the disadvantages of mesh size not being specifically adapted to archaeological work, having sides too high for objects to be easily located and picked out and being of insufficient volume for fast and efficient work. Finally, there are sieves designed especially for archaeological work. These must be custom built and are costly in terms of both time and money. 
     One such design comprises a stack of shallow-box like sieves resting on a roughly cubicle frame which is stationary and rests on the ground. It is not dissimilar to the conventional sifter described above except for its more permanent construction and the fact that it consists of a stack of sieves rather than a single sieve. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention comprises an archaeological sifting basket, in which a frame defines four walls and a bottom wall, the bottom wall having a front and rear planar area arranged at an angle to each other. The frame also defines an open top. The frame may be of lightweight metal strap, plastic or any other durable material, having wire mesh screen attached thereto, providing maximum sifting area. At certain of the intersections of the side walls with the front, back and bottom walls, hinges are provided and at the remaining intersection the adjacent walls may be separated so that the basket may be folded into a compact unit with all separate pieces contained within the interior of the folded basket for easy transport in a knapsack or other container to various dig sites in the field. The basket includes a removable handle comprising an extended gripping portion and a perpendicular brace, said brace having an opening adjacent the gripping portion so that the handle may be gripped with one hand. The basket may be utilized at the dig site leaving one hand free for brushing earth and other matter into the basket, and one or both hands may then be used to agitate the basket causing small particles to filter out, into a bucket, bag or other container, and leaving larger particles in the basket. 
     The bottom of the basket has two planar areas positioned at an angle to one another. The rear planar area is of such an extent as to support the basket in a stable condition in a first position with the opening of said basket substantially horizontal. The front planar area of the bottom is of an extent sufficient to support the basket in a stable condition in a second position with the opening of said basket positioned in a plane at an angle to the horizontal. This enables the basket to be tilted forward to rest upon said front planar area of the bottom, thus lowering the upper front edge of the basket with respect to the horizontal surface of the dig area being worked. This, in turn, enables the continued usefulness of the basket after the horizontal surface being worked is lowered to the upper edge of the basket when in said first position, without the necessity of digging down to a lower plane on which to rest the basket. It is only necessary to tip the basket to its second position for the archaeologist to continue working the same horizontal surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The construction and operation of the invention both in its preferred embodiment and its general application will be apparent to those skilled in the art, from the following specification and drawing in which: 
     FIG. 1 is a perspective view of the fully assembled basket; 
     FIG. 2 is a perspective view of the fully collapsed basket; 
     FIG. 3 is a perspective view of the partially assembled basket; 
     FIG. 4 is a horizontal cross-sectional view taken along line 4--4 of FIG. 1; 
     FIG. 5 is a cross-sectional view taken along line 5--5 of FIG. 2; 
     FIG. 6 is an exploded perspective view, showing a portion of the rear of the basket prior to securing the handle and support members to the basket; 
     FIG. 7 is a perspective view of the rear, bottom and front walls of the basket, similar to FIG. 1, showing the invention as modified by alternative placement of the bottom hinge; 
     FIG. 8 is a somewhat schematic side elevational representation of the basket in use in its upright position at a dig site; and 
     FIG. 9 is a somewhat schematic side elevational representation of the basket in use in its forward position at a dig site. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 represents the fully assembled archaeological sifting basket having four generally upright walls, a front wall 2, side walls 4 and 6, and a back wall 8. The basket also has a bottom wall having front and rear planar areas 10 and 12, respectively, meeting along a line 14, and arranged at an angle hereinafter explained. 
     Each of the walls 2, 4, 6 and 8 and the bottom wall planar areas 10 and 12 are made up of a frame to which is secured wire screen mesh. For example, the left side wall 4 has a frame 18, with screen mesh 20. The remaining walls and the bottom sections are constructed in generally the same manner. 
     The rear wall 8 has an additional frame member 22, which supports a handle 16, having a downwardly extending brace 17, including a tongue 26 removably engaged in a U shaped channel 24 welded to frame member 22. 
     The handle 16 is also attached to the additional rear frame member 22 by means of a bolt 28 passing through an upwardly extending portion 15 of the handle 16, the frame members 22 and 23 secured by a nut 27 (See FIG. 6). The bolt 28 also passes through eyes 29, 31 on tension members 30 and 32, respectively. 
     The tension members 30 and 32 have eyes 33, 35, respectively, at their forward ends through which bolts 34 and 36, respectively, pass. The bolts 34, 36 also pass through front frame member 37 and bent over ends 39, 41, respectively, of side frames 43, 45, respectively. Suitable nuts are then threaded on the bolts 34, 36 only the nut 38 for bolt 34 being shown (See FIG. 4). 
     Hinge members, which may be piano hinges as shown, or any other suitable equivalent structure, are provided at 40, 42, 44 and 46 as shown so that, after removal of handle 16 tension members 30 amd 32 and bolts 34, 36, 38 the basket may be folded for transport. Hinge 40 allows front wall 2 to be folded downwardly toward and to lie against the front bottom section 10. The bottom front planar area 10 and the forward portion of bottom rear planar area 12 are then folded upward about hinge 42 until hinge 40 bears against the upper edge of the rear wall 8. Side wall 4 is then rotated about the axis of hinge 44 so that side wall 4 lies against rear wall 8. Then side wall 6 is rotated about the axis of hinge 46 to lie against side wall 4. 
     The completely folded basket is illustrated at FIGS. 2 and 5, which also illustrate placement of the handle 16 in the interior cavity formed by the angle at which bottom planar area 10 and 12 meet. 
     FIG. 3 illustrates the partially assembled basket. The left side wall 4 has yet to be rotated about the axis of hinge 44 and secured to front wall 2 and tension member 30 by nut 38 and bolt 34. In FIG. 3 a section from the top of side wall 4 has been cut away so that attachment of the handle 16 (after assembly of side wall 4 to the front wall 2 or above described) can be illustrated. 
     FIG. 7 illustrates an alternative placement of hinge 42 so that it is at the rearward edge of planar area 12. 
     FIGS. 8 and 9 illustrate one example of the basket&#39;s application in the field. In the course of excavation, there are several different horizontal levels of digging at any one time, because squares are dug at differing rates. FIG. 8 illustrates the basket in the upright position on one such level D, i.e. the floor of a trench of square or a shelf within a trench. Earth is taken from level A and brushed or scooped into the basket, the basket is then lifted and agitated over a pail, plastic bag or other receptacle for later removal from the site. This process may be repeated numerous times between levels A and B if the archaeologist seeks great accuracy in location of objects. If great accuracy is not required, the archaeologist may go from levels A to B or even from A to C with only one sifting. 
     One advantage of the invention is that it allows earth to be sifted in any amount from a spoonful to an entire basket full, depending on the degree of accuracy required and the delicacy of the work. Another advantage is that sifted earth from the excavation site, which is waste material, may be removed by assistants, rather than by the archaeologist, that it may be transported to any area, and that, if plastic bags are used, it may even be moved from one place to another if further excavation is required. 
     The angle in the bottom wall of the basket between planar areas 10 and 12 serves a dual function. First it allows the front edge of th basket to be lowered, as illustrated in FIG. 9 so that after the archaeologist has moved the material between level A and level B (FIG. 8) he may tilt the basket to go from level B to level C (FIG. 9). 
     Secondly, tilting the basket forward raises the rear wall of the basket providing a surface which deflects earth down into the basket. This is particularly valuable when the archaeologist is working a flat surface. Rather that lifting a scoopful of earth at a time and placing it in the basket, he may flick or brush earth toward the basket. The rear wall prevents the material from flying over the rear of the basket by deflecting it so that it falls down inside the basket. 
     The included angle between the forward and rear planar areas 10, 12 of the bottom may be any angle greater than 90° and less 180°; however, an angle of between 120° and 160° has been found more useful with an angle of from above 140° to about 150° being presently preferred. 
     Important to the strength of the basket while insuring light weight are the tension members 30, 32. They need be only very small in cross section and may be wire, chain or the like, yet since any weight in the basket acts upon them to tension them they impart considerable strength to the basket, particularly the front.