1	Phytoliths as Artifacts: Evidence of Threshing on Silica Bodies Dr. Linda Scott Cummings Paleo Research Institute Golden, Colorado USA
2	Climate: Climatic has always affected human behavior. Today I’d like to examine briefly the effect of climate on agriculture and the origin of agriculture during the past. People’s choice of places to live is based, at least in part, on climate. Development of agriculture probably was affected by factors including climate and population pressure, among other things. Once agriculture developed, the ability to sustain crop yield is definitely affected by climate.
3	Archaeoclimatic Modeling (Macrophysical Climate Model): The thermodynamic/hydrodynamic consequences of the global boundary conditions which determine the concurrent array of weather patterns” (Bryson and Bryson 1995: 2).
4	Archaeoclimatic Modeling: This macrophysical climate model consists of three major segments. 1st: “largely thermodynamic calculation of the mean surface temperature of each hemisphere using the calculated incoming radiation (including Milankovitch cycles) at the top of the atmosphere as attenuated by volcanic aerosols and reflected by a ground and sea surface with modeled ice cover.
5	Archaeoclimatic Modeling: 2nd: is largely hydrodynamic, using the work of Smagorinsky (1963) to calculate the latitude at which the westerlies become dynamically unstable, i.e. the latitude at which the westerlies break off from the circumpolar vortex to produce the great eddies known as the subtropical anticyclones” (Bryson and Bryson 1995:2) 3rd: “to use the equation of Smagorinsky one must calculate the meridional variation of temperature in the atmosphere, but this is a simple function of the hemispheric mean temperature (Bryson 1992)” (Bryson and Bryson n.d.:2).
6	Archaeoclimatic Modeling: Contact Reid A. Bryson, Center for Climatic Research, University of Wisconsin, Madison. Once the model is constructed, it must be compared with field data. Vegetation varies in response to climatic conditions, such as temperature and precipitation.
7	Macrophysical Climatic Model for the Near East Using Jarmo, Iraq as the Proxy Note the positive water balance prior to 10,000 BP 10,000 to 8,000 BP conditions have changed to nearly equal precipitation and potential evapotranspiration – meaning a change in vegetation and availability of food. This is the interval in which agriculture developed After 8,000 BP evapotranspiration increases rapidly, indicating need for irrigation to sustain agriculture
8	People’s Response to Changing Climate: As mean annual precipitation fell and potential evapo-transpiration rose, conditions between 10,000 and 8,000 BP made exploitation of wild resources more difficult, and concentration of resources, which results from agriculture, more attractive.
9	Cut Phytoliths: Sheet epidermal phytoliths exhibiting smooth cuts occur experimentally and ethnographically only by threshing cereals using the bladed threshing sledge. Recovery of cut phytoliths provides archaeological evidence that this complex instrument was pulled, probably with draft animals, on prepared threshing floors soon after cereal domestication. Neolithic hearths in Jordan Storage units, and mudbrick in Syria
10	Cut Phytoliths: Early Bronze Age samples provide identification of threshing floors and use of the threshing sledge Sites in both the Negev Desert, the Northern Levant, and Syria contain cut phytoliths that show the sledge was used to chop straw, which was then used to build mudbrick walls for both dwellings and granaries and as animal fodder.
11	Evidence for Early Agriculture in the Near East: Macrofloral remains, such as charred seeds, provide the bulk of the information Cut phytoliths are beginning to provide good evidence of the use of the threshing sledge, which is substantiated to at least 8,000 to 8,700 years ago in Syria and Iraq (Anderson 1999:142 Anderson (1999:143) reports the presence of cut phytoliths associated with threshing sledges experimentally, and recovery of cut phytoliths from a Late Neolithic site at Halulu, Syria, approximately 8,500 BP.).
12	Evidence for Early Agriculture in the Near East: Cummings (2001) notes the presence of cut phytoliths in a Neolithic hearth that yielded a radiocarbon age of approximately 8,000 BP.
13	Additional Cut Phytolith Evidence: Phytolith analysis of ash deposits in a kiln in Syria dated to approximately 2500 BC, to identify fuel. Cut phytoliths recovered, indicating threshing using a threshing sledge and use of chopped straw as animal fodder, which was subsequently burned in the kiln as fuel. Kiln was filled will over-sintered pottery (stacked wasters), indicating temperatures of over 1000 C.
14	New World Threshing Floors
15	New World Cut Phytolith Evidence: Adobe brick from 1804 church at Santa Ines Mission, central California. Archaeologists felt that threshing floor might not date to the first year of the mission, which is represented by the adobe brick.
16	New World Cut Phytolith Evidence: Stone threshing floor observed at the site (Tremaine 1992). Identified initially as a stratum of cobblestones. Historic records (Webb 1952) of circular threshing floors paved with round stones, beaten earth, or fired bricks (Tremaine 1992:35) Tremaine (1992:35) interprets the presence of threshing floor to indicate treading to thresh grain, based on historic documents. Tremaine (1992:35) indicates threshing was introduced after Columbus’ second crossing of the Atlantic in 1493 (Bauer 1986, 1987), describing the Spanish as “traders, having inherited the techniques of the Romans and Arabs in earlier centuries” (Tremaine 1992:35).
17	Adobe brick examined for phytoliths in 2000 by Cummings. Cut phytolith recovered while scanning slides. Cut phytolith indicates presence of threshing sledge, indicating that new interpretation of threshing floor is necessary.
18	Adobe brick examined for phytoliths in 2000 by Cummings. Recovery of cut phytolith indicates transport of threshing sledge technology from Old World to New World. Further dictates additional research on threshing floor at Santa Ines Mission and 2 other missions in California that exhibit threshing floors Mission San Antonia de Padua Rancho San Marcos (Mission Santa Barbara)
19	Previous Analyses of Threshing Floor at Santa Ines: Previous analysis of threshing floor at Santa Ines restricted to macrofloral only. Contents include: alfalfa, barley, wheat, maize and agricultural seeds (Miksicek n.d.)
20	Previous Analyses Adobe Brick at Santa Ines: Previous analysis of adobe brick restricted to macrofloral and pollen. Macrofloral contents include: wheat, carrot, olive pit, and introduced weeds including cheeseweed, red-stem filaree, sow thistle, and sleepy catchfly (Honeysett 1989:177). Honeysett questions original of the brick based on evidence of agriculture. Pollen contents include Zea mays (maize), and cereal grain pollen, among others (Duncan 1989:191). Duncan interprets the presence of pollen from cultivated plants as evidence that agriculture predated the founding of the mission.
21	Previous Conclusions at Santa Ines Mission: Treading or flailing used to thresh grain on cobbled threshing floor Wheat to barley ratio approximately 15:9, based on harvest yield records between 1804 and 1832 (Engelhardt 1915:535 in Tremaine 1992:40).
22	New Conclusions at Santa Ines Mission: New conclusions based on recovery of cut phytoliths: Threshing sledge used to thresh grain on cobbled threshing floor First indication that Spanish brought their threshing sledge technology to the New World
23	Threshing in Spain
24	The Importance of Cut Phytoliths: Recovery of cut phytoliths addresses a number of questions, depending on geographic location and time period examined. Cut phytoliths can be used to identify the presence of: Threshing sledge technology near the beginning of agriculture in the Near East Threshing sledge technology at any time period Transfer or transport of technology to new geographic areas