And now for some archaeology from the field:
There are many different types of excavation units. The main difference between them is SIZE. How do you determine which kind of unit to use? This is also dependent on SIZE, of the site. Well, maybe not so much size, as type. Digging up a structure is different than digging up a sparse scatter of artifacts (see above).
Follow the link of that image and you can read all about Takeshi Inomata’s strategy for deciding which types of units to dig at the Mayan site of Ceibal. That link will also bring you to the NY Times’ “Scientists At Work” blog, which is pretty cool.
(*Update- the link for the photo has been fixed.)
Back to units:
You can see that there are two vastly different types of units displayed so far. The first one is called a shovel test probe, or a shovel probe. It is a 25x25cm unit, I think Bill only dug down to about 30cm. Tiny little unit. The second unit is called the “Big Pit” at Ceibal. It is an excavation into a structure at an ancient city. Takeshi Inomata says the reason this unit is so deep is, “because we have to take into consideration Ceibal’s unusually deep sequences of constructions…”
As a CRM field tech, I have yet to dig a unit that large or that deep. I probably will not ever dig a unit like Dr. Inomata’s Big Pit. Instead, I dig lots of little shovel test probes (STPs). STPs are useful in quickly determining the depth and breadth of a site. However, STPs are less precise than a regular 1x1m unit. This is due to their size. It is hard enough to get a good picture of a site from 1×1, in a unit that is 1/4 that size it is almost impossible. An STP can really only tell you about the depth of a site, which is great for management purposes. And that is why CRM field techs dig lots of STPs.
Here is Bill again taking a look at his unit: