An Answer to Graham Hancock

Last November (2000) Graham Hancock issued a public challenge to me on the Message Board of his website to read the appendix posted there in the “Horizon Scandal” section (at Hancock’s Site). This appendix reprints the interview he conducted with the BBC Horizon team on radiocarbon (C-14) dating. The appendix highlights what was actually aired from the extended interview. Clearly believing his ideas to have been grossly misrepresented, he asked if the BBC’s procedure seemed fair.

Before I begin, I should note that in his interview Hancock seemed to think that the object of archaeology is (I quote):

to deprive [a site] of all mystery and render it as boring and predictable as possible, I think it would be nice if orthodox scholars approached it [Tiwanaku in Bolivia] with a slightly more generous and a more open attitude, and at least a willingness to be amazed, rather than writing that off at the outset.

Mr. Hancock is entitled to his opinion, of course, but I thought the purpose of archaeology was to throw light on secrets of the past. If Mr. Hancock finds that past boring, that is his problem, not archaeology’s. It also strikes me that Hancock is here making a rather cheap powerplay for the allegiance of his audience:

I am the one with wonder in my heart; the scholars just want to make everything boring.

I hope few are fooled by such a tactic.

I carefully read the “Arts of the Cutting Room Floor” appendix numerous times. I determine the following points:

• 1). Had Hancock’s full statements been aired, they’d have been embarrassing for all concerned, since his “well worked out position” on C-14 dating is in fact an amalgam of uninformed and ignorant assertions about this dating method.
• 2). The broadcasted portion of the interview fully reflected Hancock’s “methods” and indicated to the public how slipshod his “extensive research” really is.

Let me now elaborate on each of these points.

1). C-14 and other forms of dating. Hancock’s position on C-14 dating, as presented in this interview, borders on the ridiculous. Had the BBC aired it, along with the simple truth about how this method of dating actually works, Hancock, the BBC, and the audience would all have been embarrassed.

According to Hancock’s interview, his main objections to C-14 dating are threefold, listed below in descending order of importance, with excerpts from his BBC interview quoted as verification:

a) C-14 cannot date stone, therefore it is not reliable in dating megalithic sites. Hancock:

Well, it beats me how a block can be dated using radiocarbon … I think that first of all there’s a degree of ignorance about carbon-dating. There’s a tendency to believe that its some sort of infallible, foolproof method that can be applied to any ancient site at any time, and it can’t be applied to stone. This is a very important point. And when we’re dealing with sites that are made of huge stone megaliths I think it may be a little bit hasty to date the creation of those megaliths to the same date as some organic material that has been found associated with those megaliths. And that’s one of the main problems that I have with carbon-dating.

b) The C-14 dates reflect only one period when a site was occupied and may not reflect earlier, busier occupations. Hancock:

And carbon-14 dating, for me, says that this site was used and occupied at the date that that carbon-14 material comes from. It doesn’t mean that the site was necessarily built at that time, or was originally laid out and planned at that time.

c) C-14 dates may not reflect all the occasions when stones were moved about and put in place, which could have been many times over the years. Hancock:

If we look underneath the block and find organic material under the block then we can say that that block was placed on top of that organic material at a particular date – which does not preclude the possibility that the block has been moved around several times and that the temple we have on Tiahuanaco has been constructed and reconstructed again and again over thousands of years. This is perfectly possible and cannot be ruled out by the carbon-dating at all. And [since C-14 is] applied to organic materials, we have to make an assumption that the organic artefact that we have found arrived at the site at the same date as the site was made – and that assumption may not be correct.

Before analyzing these flaccidities, I note a fourth one here, a new and novel dating method Hancock proposes for archaeology in the future. That is, dating sites by feeling:

the site [Tiwanaku] feels wrong for the date range that is ascribed to it by orthodox archaeologists. It just feels older.

A technical question: does adopting a yoga position increase the accuracy of “felt” dates for ancient sites? Presumably, if his case required a site to be more recent than “orthodox” thinking allowed, it would have “felt” more recent to Hancock. This, however, is not historical argument but farce.

Let us return to Hancock’s main objections to C-14.

a). C-14 can’t date stones.

Well, this is obvious. It is also entirely irrelevant. Let’s assume, for the moment, that C-14 COULD date stones. What would such dates show? They would reveal the age of the stone itself, and therefore render dates in the millions, not thousands of years. While such data might be of interest to geologists, it would be of no interest to archaeologists, who are concerned with when the stone was quarried, moved, and put in place by humans. To find that out, archaeologists would be looking at associated material to date the human activity by which the stone had been manipulated. And that is precisely what they do. So whether or not C-14 can date stone is entirely beside the point. By launching such an objection Hancock displays a profundity not of argument but of ignorance.

b). C-14 is not a reliable guide to human activity at a site.

Another embarrassing display of gross ignorance concerning even basic archaeological methods. Such information is readily available in many first-year introductions to archaeological techniques, but such difficult texts obviously evaded Hancock’s “extensive research.”

For full information on how C-14 actually works, see this site. In short, the system works as follows. First and foremost, it dates organic material found in archaeological context. Archaeological context is usually sealed strata of occupation, layer upon layer from the bottom (oldest) levels of a site to the upper (most recent) strata. The strata are carefully recorded and, gradually, the stratigraphy of the site is mapped. Often the stratigraphy is determined by smallish excavation trenches (in some cases supplemented by numerous core samples) made at various points in a site, to be sure you are not getting an imbalanced or unrepresentative picture by focusing only on one small area.

This standard procedure, by the way, renders irrelevant Hancock’s argument — stated twice in the Horizon intervieww and so an important point for him — that since only 2% of Tiwanaku has been excavated all conclusions about its date are moot; at Tiwanaku, the 2% of excavation is dotted around numerous locations all over the site: there is no reason, therefore, to expect that this pattern of digs, carefully selected for the greatest potential, is unrepresentative of the site’s overall stratigraphy. It also makes nonsense of Hancock’s Westminster Abbey analogy: archaeologists try to avoid dating entire sites from one sample of C-14 material taken from one small area of a large site. And, in any case, C-14 is just one weapon in the archaeologists’ dating arsenal (more below). Hancock claims that it is “irreponsible” for archaeologists to draw conclusions from this 2% sample of the site. In fact, it would have been “irreponsible” for the BBC to air such a claim without Hancock substantiating it. But he doesn’t; he just makes it. Presumably, if 10% or 20% or even 50% of the Tiwanaku were excavated, Hancock could still claim that a large portion of the site was not yet properly understood. Into that unexcavated portion one can then shovel anything one liked (the lost civilization, ET landing sites, Israelite tribes, the Welsh — why not?). But the burden of proof is on Hancock to prove his claims, not on archaeologists to excavate 100% of a site to show that his claims are false. Nothing found at Tiwanaku to date validates Hancock’s claims; far from it, the evidence categorically invalidates them.

If Hancock presented evidence that the C-14 sample at Tiwanaku was unrepresentative, that would be a different matter. But he doesn’t. Rather like a defence lawyer combatting evidence damning his client, he just plants an alternative claim in the mind, without substantiation. But history deals in rational analysis of hard evidence, not semantic argumentation over unsubstantiated possibilities.

In fact, when the conditions are right (as they are Tiwanaku) C-14 datable material emerges from many levels of occupation at a site, not just one. His argument that C-14 cannot date the full picture of human occupation is therefore at best grossly misleading. It can. What would indeed be surprising would be to find that C-14 dated the earliest possible human occupation of a monumental site like Tiwanaku to 1500 BC, but showed no evidence of the proposed occupation for the alternative date of 15,000 BC or for any period between then and 1500 BC for the same site. This would be surprising, since that earlier human occupation had left not a single vestige of its presence, while the later occupation of 1500 BC and all subsequent occupations were so readily identifiable in the archaeological record. To build huge monuments, this earlier proposed population would presusmably have been numerous and well organized, whereas the initial occupants of 1500 BC were not numerous or well organized. Why should paltry occupations be so easily tracaeable but the supposed earlier and more major inhabitations remain invisible to us?

There is, of course, a straightforward scenario that explains the evidence: there was no earlier occupation. Unless evidence surfaces for such an occupation, there is no reason to suspect it existed. That is what the “orthodox” scholars conclude, drawing from the evidence at hand.

On a side note, C-14 is not infallible (what human process is?), but as many correctives as possible are employed to limit the impact of error: samples, typically, are sent to several laboratories who date them “blind” (without any indication of where they came from) and C-14 is just one element in a chronological assessment of a site (supplementing pottery analysis, stratigraphic analysis, artisitic development of monuments, and so forth). In this overall analytical context, C-14 is about as reliable and trustworthy a method of arriving at reliable dates as one can find, but it is not infallible. Samples can be corrupted and throw the dates off, mistakes can be made. In the case of Tiwanaku, however, 29 C-14 dates were arrived at, from archaeologically verified contexts. Those dates were internally consistent (i.e. material from lower strata dated earlier than material from upper strata, as you’d expect). There were anomalies, of course, but nothing to make one suspect that the overall picture painted by the C-14 dates was out by a margin of ten centuries. All this, in conjunction with pottery analysis, strongly suggests that the chronology derived from the C-14 dates for Tiwanaku is reliable and there is no reason to suppose the C-14 samples have been corrupted or are misleading us. Yet Hancock just ignores them on the grounds of the objections he raises above.

In reality, this is all very basic stuff. The appropriate procedures are explained in any standard handbook on archhaeology. I suggest to Mr Hancock that before he sets out to revolutionize a field of knowledge he first gain at least a passing acquaintance with the basic procedures of that field.

c). The stones could have been moved.

I’ve read this several times and I still fail to see Hancock’s point without sliding into absurdities. Let’s take an example. If we find Stone A in a C-14 dated context of, say, AD 200 Hancock appears to be saying:

it could have been put up somewhere else earlier and moved about before coming to this spot.

But since we’re interested in when the stone got to be where it is now and to date that action, it makes no difference if Stone A went backpacking in Europe before settling into its C-14 dated location of AD 200. To all intents and purposes, that IS when it was set up. It would, indeed, be interesting to chart the travel histories of stones, but we have no way of doing so, without evidence. Unless someone can point to where Stone A stood previously and can identify, say, the now-empty socket-pits that once held it, we can speculate ad nauseam about Stone A’s fascinating pre-AD 200 peregrinations. But what’s the point? Once more, Hancock’s “argument” is merely an empty possibility raised without substantiation for the sole purpose of extracting him from a difficult position.

Hancock also argues that the temples at Tiwanaku could have been built and rebuilt numerous times over the centuries. Why? What evidence does he have for this contention? Why did the ancients keep laboring on the same site, with the same stones, on the same groundplans? To be sure, we do have pagan sites in Europe that were re-used or torn down and rebuilt (usually somewhere else) as churches. We also have Egyptian temples, as Hancock say in the interview, that were built and rebuilt over centuries. And Maya pyramids. And Mesopotamian palaces and ziggurats. But the very fact we know all this shows that such actions are readily recognizable to a trained archaeologist. And there are no indications at Tiwanaku of any such obsessive rebuilding activity. What we don’t get are temples torn down again and again and rebuilt with the same materials, on the same site, and on the same plan in a way that makes this process impossible to detect. It is also entirely illogical. Why would people waste their time doing this? So why raise this possibility at all, without any evidence that it applies? This is just more legalistic argumentation from Hancock.

Another crucial point here is that if, as Hancock argues, the stones of Tiwanaku were on the move over the centuries before settling into the locations they occupy today, that surely delivers the final killing blow to all his arguments about star-alignments helping to date the site to 15,000 – 10,000 BC. By his own argument, the stones weren’t necessarily always in the same place. This is another typical mode of argument for Hancock: he argues a specific point to the hilt without any concern for overall consistency.

Finally Hancock argues that:

[Since C-14 is] applied to organic materials, we have to make an assumption that the organic artefact that we have found arrived at the site at the same date as the site was made – and that assumption may not be correct.

As I see it, there are only two conceivable alternatives here:

1) The organic material was there when the stone was set up over it. In that case, it does date the EARLIEST possible date when the stone was set up in that spot. To be sure, the stone could have been set up long after the C-14 date (the organic material lying in the ground long before the stone was put over it), but it cannot be any earlier. Since Hancock is arguing for earlier and not later dates, this possibility in no way helps his case. (Archaeologists, by the way, correct for this possibility by looking at the overall cultural record of the site: large stone construction usually come with large populations living in houses and using pottery and so on.)

2) The other possiblity is more useful for Hancock’s case: that the organic material was inserted under the stone AFTER it was set up, thus dating the stone to a later date than its actual erection. But how likely is this? How did the later material get lodged there? Does Hancock envisage a band of C-14 saboteurs running about inserting pre-dated material under ancient stones to throw off archaeological dates? And wouldn’t the trained eye of an archaeologist identify a secondary dig pattern, the hole dug to insert the material? Organic material can be moved by natural means (root action or small burrowing animals), but are we to assume that all 29 C-14 dates at Tiwanaku are contaminated, and such a way as to be internally consistent? I’m afraid this scenario is far more unlikely than the first one.

So much, then, for Hancock’s “well worked out position” on C-14 dating that the BBC did not air in full. Despite it being one of the most useful methods of dating in archaeology for the past half century, Graham Hancock has, for the tendentious reasons listed above, determined that it is in fact useless. He honestly seems to think that archaeologists should rely instead on their feelings.

In his BBC interview Hancock reveals much about his mode of argument that, in closing, it may be useful to document here. Basically, when faced with hard evidence (here C-14 data that make rubbish or his proposed early dates for Tiwanaku) he resorts to raising possibilities. The only merit of these possibilities, the only reason they exist at all, is to support his case. There is no independent evidence to support any of them, and none is offered. In many cases they run contrary to the observable evidence. They are just possibilities that have the commendable quality of digging Hancock out of a hole.

I have highlighted examples above. But to illustrate just how absurd such a method of “argument” is, let me illustrate with an non-archaeological hypothetical example.

Q: Did you eat that last piece of chocolate cake?
A: No.
Q: But there are chocolate crumbs on your lap and chocolate smears on your lips. The evidence would suggest that you did.
A: Perhaps. But a third party could have come in there and eaten the cake and then smeared my lips and sprinkled my lap.
Q: Do you have any evidence for that reconstruction?
A: No. But it’s a possibility.
Q: OK, so why didn’t you resist this third party?
A: I could have been incapacitated somehow.
Q: Can you show any evidence of incapacitation?
A: No. But it’s a possibility.

With such a mode of argument, are we in the world of reason or a Monty Python sketch?

Hancock’s appeal to the opinions of Bolivian archaeologist Oswaldo Rivera (who supports his early date for Tiwanaku) is the height of disingenuousness. It seems that Hancock can cast the opinions of archaeologists wholesale into the garbage – unless they agree with him.

Hancock’s BBC interview on C-14, as posted to his website, thus speaks volumes as to his ignorance of even basic archaeological procedures and his tendentious mode of argument from conceivable possibilities rather than evidence when faced with hard data that demolishes his case.

As it is, the BBC aired two essential statements from the interview:

I’m not required to be encyclopaedic.

Indeed not. It seems Hancock isn’t even required to read introductory texts in the field he is are proposing to turn on its head.

In Heaven’s Mirror there is no representation whatsoever of recent carbon dates for Tiahuanaco. I simply didn’t discuss it in there.

That Hancock choses to ignore this vital information – which his readers may have found compelling – speaks volumes about his methods. That he did not even set out his “well worked-out” position on C-14 in Heaven’s Mirror is also significant. Apparently, he feels that having allusively raised his objections to the method in Fingerprints of the Gods he is now at liberty to dismiss any inconvenient C-14 material in blanket fashion. No need even to mention it.

But unlike “alternative thinkers,” real inquirers into the past do not have the option of knowingly ignoring data that contradict or undermine their case. Nor do they have the option of dismissing out of hand, on the basis of conceivable possibilities, long-accepted modes of analysis that make rubbish of their pet theories. That’s why true historical inquiry actually gets somewhere, instead of wandering about endlessly in the wastelands of speculation.

SEAN HANCOCK

In Dec. 2000 and January 2001, Graham Hancock’s son (Sean) posted two articles to Hancock’s website (What is Radiocarbon Dating and is it a Reliable Method of Dating Archaeological Sites? and An Interpretation and Critique of the Radiocarbon Database for Tiahuanaco) that attempt to undermine C-14 dating in general, and the C-14 dates at Tiwanaku in particular. While clear on the technicalities of the C-14 method, Sean displays little ability in interpreting the data he uncovered. I’ll take three key points he makes:

1). Problems with C-14 dating in general. That Sean had no trouble tracing the various problems and uncertainties in C-14 dating is a clear testament to the fact that these problems and uncertainties are well known to professionals and have been long understood. C-14 is but one method in dating sites and, whenever possible, is never used in isolation from other methods. Sean admits as much when he states:

Radiocarbon dating is useful as a compliment [sic] to other data; this is when it is strong.

He is stating the obvious here. Methods of analyzing C-14 material are constantly being improved and updated by physicists. His highlighting of admitted errors in the C-14 method in the past only illustrates the self-correcting nature of scientific knowledge.

2). Inconsistent dates at Tiwanaku. Sean Hancock lights on 2 samples of the 29 taken from Tiwanaku to attempt to undermine the entire C-14 evidence for the site. Sample GaK-194, from the large monument called the Kalasasaya, dated to 3530 BP, ± 120 years (ca. 1530 BC). But even the excavators were wary of this date, commenting:

unexpectedly old compared with GaK-52 (dated to ca. 190 BC) and cultural epoch.

This one sample, then, appears to be corrupted. Sean berates the analysts:

If the dates don’t fit the archaeological hypothesis they are simply ignored.

Not so. If the dates don’t fit the OTHER CONSISTENT EVIDENCE, they can assume to be corrupted somehow, unless new evidence shows otherwise. Given the difficulties and uncertainties in C-14 dating that Sean himself has spent six pages writing about (see #1 above), this hardly seems unreasonable.

Another sample (Hv-17) attracts Sean’s attention. This also comes from the Kalasasaya and dates to 240 BP, ± 80 years (ca. 1760). Sean is unclear whether this sample comes from below, under, or beside the Kalasasaya. But the record is clear: “

From 50 cm depth, from the ceremonial platform of Kalasasaya … Sample was later proved not to belong to the culture layer.

In other words, the sample was just below the surface on the ceremonial platform, not underneath it, nor beside it, nor indeed associated with the Tiwanaku material at all. It tells us nothing about the original occupation. The late date of this sample, in fact, only further illustrates the disturbed nature of the site that renders impossible any dates drawn from the supposed star-alignments of some of its stones. And some intruded later C-14 material does not imply that all the C-14 found has been similarly intruded or is unreliable (as Sean Hancock tries to suggest). You’d have to substantiate that claim by evidence, not innuendo.

The basic facts for Tiwanaku stands. 29 C-14 dates were recovered in the late 1950s, 1980s, and 1990s. Three of those dates are anomolous and reflect the disturbed nature of the site (see below). The rest are consistent, tie in with pottery evidence from the site, and paint a picture of the city as flourishing between ca. AD 100 and 900.

For clarity’s sake, here are all the C-14 dates from Tiwanaku (since the samples were collected in the late 1950s, 1980s, and 1990s, the absolute dates are approximate, ± 40 yrs)

Gak-194 (Kalasasaya, layer 6, Epoch I), 3530 ±120 BP (ca. 1530 BC)
Gak-195 (Kalasasaya, layer 5, Epoch II), 1750 ±100 BP (ca. AD 250)
B-488 (Kalasasaya, level 7 (-255cm)), 2400 ±200 BP (ca. 400 BC)
B-489 (Kalasasaya, level 7 (-270 BC)), 2530 ±200 BP (ca. 530 BC)
B-490 (Kalasasaya, level 6, layer 4), 2100 ±120 BP (ca. 100 BC)
ETH-5639 (Akapana), 1090 ±60 BP (ca. AD 910)
ETH-5640 (Akapana), 1090 ±85 BP (ca. AD 910)
Gak-51 (Kalasasaya, layer 3), 630 ±110 BP (ca. AD 1370)
Gak-52 (Kalasasaya, layer 6), 2190 ±130 BP (ca. 190 BC)
Gak-53 (Kalasasaya, layer 6), 2410 ±140 BP (ca. 410 BC)
Gak-192 (Kalasasaya, upper part of layer 7, Epoch I), 1990 ±110 BP (ca. AD 10)
Gak-193 (Kalasasaya, lower part of layer 7, Epoch I), 1850 ±90 BP (ca. AD 150)
Hv-17 (Kalasasaya, 50 cm depth on platform), 240 ±80 BP (ca. AD 1760)
Hv-18 (Kalasasaya, 175 cm depth on platform), 1630 ±130 BP (ca. AD 370)
Hv-19 (Kalasasaya, 180 cm depth on platform), 1645 ±80 BP (ca. AD 355)
INAH-972 (Akapana), 1120 ±140 (ca. AD 980)
P-119 (Tiwanaku, level 8, 2.3 – 2.85 m down), 1460 ±200 BP (ca. AD 540)
P-120 (Tiwanaku, level 9, 2.0-2.25m down), 1702 ±103 BP (ca. AD 308)
P-120A (Tiwanaku, levels 8-10, 1.75 to 2.5 m down), 1226 ±100 BP (ca. AD 774)
P-121 (Tiwanaku, levels 6 and 7, 1.25-1.75 m down, associated with classic Tiwanaku pottery), 1423 ±175 BP (ca. AD 577)
P-123 (Tiwanaku, level 15, 3.5 to 3.75 m down; digging continued for 4.74m below with no pottery below 4m), 1817 ±103 BP (ca. AD 183)
P-146 (Tiwanaku, level 1 0.0-0.75 m down), 949 ±98 BP (ca. AD 1151)
P-147 (Tiwanaku, levels 6 and 7, 1.8-2.3 m down), 1576 ±104 BP (ca. AD 424)
P-149 (Tiwanaku, level 12, 2.75-3.0 m down), 1701 ±93 BP (ca. AD 299)
P-150 (Tiwanaku, levels 14, 3.25-3.5 m down), 1692 ±104 BP (ca. AD 308)
P-531 (Kalasasaya, 85-100 cm deep), 295 ±192 BP (ca. AD 1705)
P-532 (Kalasasaya, 3.64 m down), 1653 ±61 BP (ca. AD 447)
P-533 (Kalasasaya, 1.1-1.35 m down), 778 ±133 BP (ca. AD 1222)
P-532 (Kalasasaya, 2.15-2.17 m down), 1866 ±62 BP (ca. AD 234)

It is noteworthy how all the dates are so consistent, falling mostly in the era of ca. AD 100-900. Within each series, too, the dates are consistent: the GaK and B series have the earliest dates drawn from the lower levels of the Kalasasaya (further corroborated by the P-500 series, also from the Kalasasaya); the HV series has the anomolous later date (but not the only one, cf. P-531); even with series, the dates are as one would expect, e.g. the deeper one goes in the P-100 series, the older the dates tend to become (with fluctuations, to be sure, but not unaccountable for by the deviations).

You can’t dismiss all of these dates by focusing on two recognizedly problematic ones.

3). Depth of digging at Tiwanaku. Sean’s final argument is his weakest. Looking at sample P-123, Sean notes how the archaeologists only dug 0.75m below the last cultural layer before stopping. Sarcastically, he comments:

… Big deal! Is it so absurd or unscientific to be open minded to the possibility, however remote, that a yet-to-be identified cultural layer exists at Tiahuanaco? …

He goes on to raise the possiblity of an as-yet-unearthed ancient Tiwanaku at deeper levels, quoting Dr. Oswaldo Rivera, former director of archaeology in Bolivia:

I am sure we are going to discover the inner part of Tiahuanaco a sunken Tiahuanaco, underneath the existing one I think 12 or 21 metres down we have another Tiahuanaco, and it’s the sacred Tiahuanaco, the original.

Dr. Rivera can offer no evidence to substantiate his certainty, and Sean admits none exists. Like his father, he just raises the possibility and indirectly labels his critics close-minded for not accepting that possibility.

But there are two fundamental flaws in both Sean’s and Rivera’s possibility. First, Tiwanaku was founded on an alluvial plain. The layers below the occupation layers at the site are of alluvial mud laid down tens and hundreds of thousands of years ago. It is unlikely that the “sacred Tiwanaku” lies in or underneath this very ancient mud.

Second, both Sean, Graham, and Rivera want to have their cake and eat it too. They say that the visible stones of Tiwanaku hearken back to a lost epoch in human history (cf. Hancock’s use of star-alignments for the stones, his interpretation of carvings on the Gate of the Sun as extinct animals, etc). Yet according to Sean Hancock and Oswaldo Rivera, the occupation layers associated with these stones (which are on the surface) is supposed to be 40 or 60 ft BELOW the surface? This is an archaeological impossibility, since the surface layers of the site would not have been laid down when the occupation at 40-60 ft deep was in progress.

The fact remains that the C-14 material associated with the stones is consistent and points to a far more recent date than that favored by Sean and Graham Hancock, or Oswaldo Rivera. No amount of digging into sterile alluvial mud will change that fact.