Though Calico and many other previously inferred pre-Clovis sites may ultimately be accepted as "legitimate," the real challenge is to predict the general location and to actively explore other such sites. But where? Logically, they should occur on surfaces about 200 ka old. But such surfaces are rare owing to rapid fluvial dissection or to later covering by sediments. Indeed, most of the world's geomorphic surfaces are no older than Holocene (~10.5 ka). There are exceptions, however. For example, some remnant, high-level alluvial fans in the Mojave Desert are more than about 100 ka old, recognized by their tightly packed desert pavement, their dark- colored patina (desert varnish), and their strongly developed surface soils (relict paleosols; Shlemon, 1978). But such desert surfaces are, and were, inherently inhospitable for continued human occupance. Therefore, few high concentrations of undisturbed artifacts are likely to be found.
In contrast, the most promising, unequivocal Early Man targets are buried, often under many meters of sediments. Only a fraction of the ancient surfaces (buried paleosols) are ever seen, usually in fortuitous road or mining cuts. The most favorable Early Man targets are old shorelines that mark the junction of diverse environments, and thus are particularly susceptible to artifact concentration and preservation (Budinger, 1992).
Though rare, such paleo-environments may also be exposed in natural cuts. Ironically, one of the best Early Man "targets" are natural exposures that occur very near the Calico site. Indeed, the full acceptance of Calico may not come from collecting more on-site artifacts, but from systematic observation and possible excavations in the nearby Manix Lake beds (Shlemon and Budinger, 1990). The stratigraphy of the well exposed Manix beds is remarkable, for these beds range in age from about 20 ka to 290 ka, recording climatic and sedimentation change in this part of California for much of middle and late Quaternary time; they interfinger distal fan sediments that emanated from the Calico Mountains and other nearby "quarry sites;" they bear several datable ash beds, one of which is an estimated 185 ka, tantalizing close to the 200 ka age for the Calico artifact-bearing beds; and they contain abundant vertebrate fossils. In sum, the Manix Lake beds are a classic Early Man target. They may indeed be the place for a new breed of archaeologists and their geoscience colleagues to explore unabashedly for pre-Clovis sites. Such endeavors are no longer far fetched, particularly in light of the recent Monte Verde and Diring discoveries.
Accordingly, it appears that we will soon see a "quiet revolution" in New World archaeology whereby mainstream archaeologists reinterpret their data and thus "document" pre-Clovis sites. If so, New World archaeology will take a giant step forward, perhaps analogous to the now-famous 1970's "plate tectonic revolution" in geology.
The year 1997 saw another break through, albeit indirect, for acceptance of pre-Clovis man in the Americas. Published in the prestigious journal "Science," Michael Waters and colleagues dated the so-called "Diring" site, a lower Paleolithic assemblage of stone artifacts in central Siberia (Waters and others, 1997). Based on deep trench exposures, the stone tools are reportedly of undoubted human manufacture. They occur in eolian sands, sediments amenable to thermoluminescence (TL) dating techniques. The cultural horizons prove to be about 260 ka old, almost 250 ka older than artifacts recovered from unconformably overlying sediments, a stratigraphic relationship similar to several, heretofore generally rejected Early Man sites in the Americas.
Uncertainties always accompany various dating techniques, and hence Diring will likely be questioned. However, the dates were obtained by a well-known geologist, a specialist in the field of TL analysis and one of the co-authors. Waters, himself, is a distinguished archaeologist. He also teaches at a prestigious American university, and thus gives substantial credibility to the 260 ka age for the Diring site.
The Diring dates have profound implications for dating the possible entry of pre-Clovis man into the Americas, for they imply that ancient stone tool makers lived and perhaps even prospered in the harsh Siberian environment; and that crossing into the New World via Beringia may have indeed taken place long before the blossoming of Clovis cultures.
I would look at the edge of old lake beds, river banks, and naturally, caves. I suspect that someone with a "trained eye" could find many interesting artifacts. As an example, looking for shark's teeth. Once one has walked the beach where they are, in a week or so, they just pop out at you. I was standing with one between my feet, and I didn't see it. My friend who lived there said, "I was standing on one." The same is true for pottery shards. Once you look for a while, where there are some, you see them everywhere.
It will be a bitterly opposed revolution and will depend on young archaeologistswho are trying to make names for themselves because the older ones will fight bitterly to suppress any discoveries that question their own assumptions. Archaeologists are some of the very most "religious" of scientists in that for them all knowledge is "received" as with an original "revelation" that cannot be challenged but can only be elucidated.