01686nas a2200169   4500008004100000245011800041210006900159300001000228490000700238520113800245653001901383653001501402653001601417653002601433100001701459856004001476       2002                        eng d00aThe Good Earthworm: How Natural Processes Preserve Upland Archaic Archaeological Sites of Western Illinois, U.S.A0 aGood Earthworm How Natural Processes Preserve Upland Archaic Arc  a53-900 v173 a<div class="para">
<p>In western Illinois, many soil profiles developed into upland loess deposits (Peoria Silt) contain Archaic period artifacts greater than 3500 yr B.P. in stone zones below plow level. For artifacts in prairie and prairie-forest transition soils (not forest soils), depth distribution curves suggest they were buried in biomantles by small soil fauna. Artifacts of sizes archaeologists routinely collect generally move down while retaining fine-scale horizontal integrity. The process results in stratigraphic separation of Archaic and Woodland period components that otherwise would commingle at the surface. The characteristic distribution of known upland sites, narrowly rimming stream valley headwaters, reflects incomplete burial of materials on steeper forested slopes. On adjacent gently sloping upper shoulder segments of valleys where grassy cover more strongly influences soil development (and by inference on broad level uplands where true prairie soils occur), Archaic artifacts will be buried in the biomantle and go undetected by surface surveyors. © 2002 John Wiley &amp; Sons, Inc.</p>
</div>
10aArchaic period10abiomantles10astone zones10aupland loess deposits1 aVan Nest, J.  uhttp://dx.doi.org/10.1002/gea.10003