Cultural Deposits in Homogeneous Natural Sediments VS. Homogenized Cultural Deposits in Natural Sediments

     Thursday’s touchstone blurt has prompted three interesting comments–two of which from long-time acquaintances; one of which was left by Edward Harris, progenitor of the Harris Matrix and author of Principles of Archaeological Stratigraphy [which the author has made freely available online–just click on the title]. 

     All three expressed dismay that any archaeological sites are still excavated in arbitrary levels, and they all added a gentle prod to the effect that I should not be so quick to accept the practice’s continued use, even for sites in California. The problem really boils down to this. California archaeologists aren’t dealing with cultural deposits in homogeneous natural sediments. They’re dealing with completely homogenized (bioturbated) natural sediments and cultural traces. That’s quite a different story, as I’ll argue further down. But right now: nail buffing time.
     The Matrix man [or so he calls himself] sent me an email in addition to leaving a comment on Thursday’s blurt, which I copy here for posterity

Hello Rob

Thank you for your kind remarks and I made a comment on your interesting blog.

How can we advance the revolution (the Matrix is 40 next February!). Perhaps I should learn how to do a blog.

Anyway, I was speaking with colleagues from Playa Vista in California, who suggest they could not have done that dig without the matrix!

Here is the first one ever made and also a little article. You can post them if you like. The first-ever Matrix (read, as we now know, “stratigraphic sequence”) was made in 1974 for the site excavated that year at the south gate into the Roman town of Winchester, England.



Edward C. Harris, MBE, JP, PHD, FSA, Executive Director

Cell: (441) 704-5480; eMail:
National Museum of Bermuda
Incorporating Bermuda Maritime Museum
Street: 1 The Keep, Sandys MA 01, Bermuda
Mailing: P.O. Box MA 133, Sandys MA BX, Bermuda
Tel: 1 (441) 234-1333    
Fax: 1(441) 234-1735

 To see his article on time and the Matrix, click here

First-ever Harris Matrix–South Gate, Roman Winchester, 1974 (Photo courtesy of E. Harris).

In what follows I’ll try to explain (and not explain away) the conundrum faced by every archaeologist in almost any landform and at almost any altitude in California. Here goes!
     Regardless of the characteristics of the parent material on and in which pre-Columbian California archaeological occupation sites have formed, and regardless of the rate of aggradation throughout the period during which the cultural materials were abandoned, there is a Nemesis against which it is futile for an archaeologist to struggle: fossorial rodents–specifically the ground squirrel (Sciuridae) and the pocket gopher (Geomyidae). These animals are prodigious breeders and tireless burrowers. And because they have been present throughout the epoch of human occupation, they have had a universal and profound, time-transgressive effect on the vertical and horizontal distribution of archaeological materials in California sites. This has been documented in numerous ways and in sites across the Golden State. 
     These animals are capable of transporting any clast smaller than their burrow’s diameter anywhere from millmeters to (eventually) meters from it original location (if that was, in fact, its ‘original’ location). At any time they are regularly disturbing the top 50 cm or so. Given their habit of pushing their backdirt upward and out onto the surface, the smaller archaeological pieces ‘liberated’ in this fashion tend to remain in the upper 10 cm or so. And larger clasts are transported generally downward because over time they are undermined and drop a few cm at a time. This can happen to boulders and everything smaller that can’t be displaced along the burrow itself. 
     The habits and ubiquity of these rodents have ensured that no site in California, and certainly no site with a longish occupation sequence, can be expected to present observable stratification or, for that matter, a vertical column that contains the oldest traces at depth; the youngest near or at the surface. Moreover, the process size-selective upward and downward displacement I’ve just outlined means that in general there is a bi-modal vertical distribution of artifacts and natural clasts.
     Donald L. Johnson’s three drawings below illustrate what can and does occur as a matter of course in (quite literally) any unconsolidated dirt anywhere in California with the exception of [and I’m guessing here] the area above the tree line. It’s necessary to read the detailed figure captions to make sure you understand what’s going on in each series. However, I’m certain that those of you who aren’t from around here will be astonished and might eventually come to accept why it is no surprise that arbitrary levels are still the state of the art in California.

Johnson. Donald L. 1989. Subsurface Stone Lines, Stone Zones, Artifact-Manuport Layers, and Biomantles Produced by Bioturbation via Pocket Gophers (Thomomys Bottae), American Antiquity, 54,  370-389.

In most non-shell-midden sites in California the average stratigraphic profile records only the following:

a. the position of the large clasts that weren’t released during excavation.

b. the presently visible rodent krotovinas

c.  a humic layer at the top of the sequence that represents where the latest decomposed vegetation has resulted in illuviation

d. any pedogenetical horizonation that may still be in evidence below where burrowing has occurred, which is often the case in what are known as ‘prairie soils’ in relatively xeric landscapes, where illuviation of carbonates creates a relatively rodent-unfriendly consolidated layer at depth. 

That’s it!
     Alas! There’s no remedy for the effects of burrowing rodents on most archaeological sites in California. In fact, the effect I’ve sketched here is so widely distributed and such a virtual certainty that when attempting to ascertain the extent and time-depth of most pre-Columbian occupation sites savvy archaeologists know that one is most likely to find an example of every temporally sensitive cultural indicator smaller than the diameter of a rodent burrow in the top 10 cm of the site, regardless of the age of a site’s cultural sequence.
     Such is life in California archaeology. I’ll stand up for my California colleagues any day when there’s any question of the professionalism evinced by excavating in arbitrary levels. There’s no other choice. We who’ve worked in California know full well that there’s little point in digging a unit to ‘sterile’ in a site that’s been subject to rodent bioturbation. We know that, more than likely, all we’re recovering is bagfulls of out-of-context cultural artifacts.
     My new, but long-admired, colleague, Edward C. Harris, MBE mentioned that the people who worked at Playa Vista in southern California told him they couldn’t have done their work without using the Harris Matrix. I’d be willing to bet any money that they were referring to their excavations of the historic remains on that massive project, and not any pristine (nominally speaking) pre-Columbian occupation sites.
     This has been fun. Have a good week, everyone.

Can You Say Reprehensible?

I suppose it’ll come as a shock to no one. The leading source of business news for the 1%, the Wall Street Journal, ran a story recently about TEFAF, the annual fine art and antique fair in the Dutch city of Maastricht that’s put on by the watchdogs of art on ‘the continent,’ The European Fine Art Foundation. I’m singling out for deprecation the TEFAF, its exhibitors/dealers, and the WSJ reporter because of the kind of ‘art’ that it and the paper are pimping.
     I was drawn to the article by a link somewhere that showed this (putatively) Olmec jade mask [clearly meant to be worn by its two-legged primate carver or the owner thereof] and proclaimed that it had been sold for 1.75 million (a lot of money).

Wall Street Journal online: ‘In the Eye of the Beholder‘ March 23, 2012 

All of my archaeologist friends will cringe at the thought, to begin with. But if they’re like me, the cringe will transform itself rapidly into closed fists and rage.
     This is how one ‘dealer’ explained his situation vis a vis the Olmec mask.

Meanwhile, … a powerful, life-size mask in blue-green jade by the Olmec people of Guatemala in 900-300 B.C. captures the eye. Representing an owl man, the haunting, supernatural creature has both human and bird-like features… . “We waited hopefully for ages before contemporary collectors moved into our market,” says Bobbie Entwistle.” And then it happened in the last three years.” Her partner, Lance Entwistle, notes that pieces at the high-end are doing particularly well, as big contemporary art collectors seek iconic objects. “Unfortunately,” he says, “supply is short.”

Boo-hoo. Bastards. If the pillage of archaeological sites weren’t already a bigger threat to world heritage than the government of Turkey, sales and prices like this’ll quickly turn the trade of illegal antiquities into a global turf war for plundering rights. And you thought cocaine was troublesome!
     Only two WSJ readers commented on this travesty of a ‘news’ story. One brought up the difficulty of authenticating such pieces. True. If there were any real authenticating going on, the dealers must be in possession of the lay equivalent of a chain of evidence going right back to the impoverished, machete-wielding opportunist who hacked a chunk of our heritage from its archaeological context. If so, it should be possible for law enforcement to bring charges of illegal trade in antiquities against each and every pair of hands that touched that piece, all the way back to the Mexican bush-whacker.
     Wouldn’t it be loverly? It goes without sayin’ that it ain’t gonna happen.
     Finally, how oblivious to the ongoing archaeological Armageddon was our thoroughly, editorially ethical, WSJ correspondent? This is how.

Among my favorites were Egyptian pieces. At Rupert Wace Ancient Art of London, a rare Egyptian relief with an image of Queen Hatshepsut, who was the first woman to rule Egypt in her own right (1479-1458 B.C.), was quickly snapped up for a six-figure sum. “From the first day, we had lots of sales,” says Swiss ancient-art dealer Jean-David Cahn. Among the pieces that went immediately were a small head of a bald Egyptian priest, from 728-525 B.C. (price: €62,900); and an exquisite, serpent-shaped, gold Egyptian bracelet, from the second century B.C. (price: €29,600). Such bracelets decorated the upper arm of Hellenistic statues of Aphrodite in Alexandria.

Hatshepsut, fer Chri… in’ out loud! And only six figures! These people may be vipers. But, they wouldn’t know a seriously important artifact from a large hole in the ground [about which us archaeologists know a great deal more]. You do the math. A jade mask of some nameless faceless Olmec owl-man garners almost twice as much as what amounts to the equivalent of a previously unknown signed da Vinci! [I hope you realize I’m only making a very bad joke–but the analogy still holds.]
     To summarize, Jeebuz! We’re all in trouble with this much slam-dunk ignorance and avarice abroad in the world.