More on New World Origins

In comments to the previous post Dior had asked for some links to sources. As I was working on a response I realized I had more to say on the subject.
First some terminological issues. The words Pre-Projectile Point Horizon actually have some meaning in archaeological jargon. The term horizon is defined, in Willey and Phillips "Method and Theory in American Archaeology" as "...a primarily spatial continuity represented by cultural traits and assemblages whose nature and mode of occurence permit the assumption of a broad and rapid spread. As applied to Clovis, then, you have a simple technology (the Southeast Asian Chopper-Chopping Tool Traditon mentioned above) which somewhere evolves a new trait (Clovis) which spreads like wildfire (in some respects it is like punctuated equilibria with it's emphasis on peripatric speciation followed by a rapid spread). Other examples of a horizon would include the spread of shell tempered pottery in the southeast and the spread of the Southern Cult, also in the Southeast.

You will also note I did not say much about skeletel remains. The reason is that with a few rare exceptions, such as the Kennewick material, skeletal material from this time range does not exist ( go here, here and here for more info on Kennewick - especially the first site). Kennewick does have an impact on the debate and I may do a post about it some time in the next couple of weeks.
Now to answer Dior.
The only magazine reference I used was from the May National Geographic. The article doesn't seem to be in the online edition. For the rest, I basically summarized part of Chapter One of Willey's Introduction to American Archaeology - a two volume classic. I would recommend it to anyone interested in archaeology. You might also check out Jennings and Norbeck's Prehistoric Man in the New World. Macgowan and Hester's Early Man in the New World is also quite good. In terms of journal articles the following are pretty interesting:

Chard 1959 New World Origins: A Reappraisal, Antiquity 33(129): 44-49
Chard 1959 Old World Sources for Early Lithic Cultures, Actas del 33ra Congresso de Americanistas pp314-320
Chard 1963 The Old World Roots: Reviews and Speculations Anthro. Papers 10(2) University of Alaska, Fairbanks
Wilmsen 1964 Flake Tools in the American Arctic: Some Speculations
Wormington 1957 Ancient Man in North America, Popular Series # 4, Denver Museum of Natural History.
Finally, for the climate stuff Butzer has a good book called "Environment and Archaeology"

The above references, you may have noticed, are from the 50's and 60's. Although old, these are the papers that set the framework for the debate over Clovis and the Pre=Projectile point horizon. As matters stand now, archaeologists are at something of an impasse older material like Lewisville, Tule Springs, Topper, Meadowcraft and Monte Verde keep cropping up, but unfortunately none of them provide definitive answers (one way or the other).

To answer Henry: My advice would be to take the point to a university anthro department. However, if you want to solve the riddle yourself I would consult Willey's book - or a similar book. Fluted points are pretty distictive - unfortunately, I couldn't find a pic where the fluting really stands out. The flutes are broad long grooves running the length of the point (Clovis and related points are spear points - you can tell by the size). I haven't read Diamond's book yet, so I can't really comment on it. There are valid arguments for the younger dates. I, personally, find the above sites (and quite a few others that are similar) to be suggestive. They are, IMHO a legitimate phenomena that needs to be explained.