Oakland Underfoot

In the last few weeks I’ve spotted five more numbers in the OPCFIA union bug. The last three are interesting to me in a new way.

What’s interesting about the last three? First, J. H. Fitzmaurice employed several master craftsmen, although that’s not a surprise. It was a big firm, probably accounting for more Oakland pavement than any other. Second, students of Fitzmaurice marks will note that the first is the fourth configuration used by this longtime Oakland company, and the other two are the fifth and last. The older mark was made by an earlier registered master, as indicated by the lower number.

The master number ought to be a secondary clue to the ages of marks, like Fitzmaurice’s, that rarely bear dates. Paleontologists will be familiar with this problem because fossils never bear dates — all we know is their position on the stratigraphic column. That’s an idealized stack of sedimentary rocks built by noting what rocks overlie or underlie other rocks. The stratigraphic position obviously corresponds to some true age, measured in years, but the only way to estimate it, even partially, is to find a secondary clue, like a bed of fresh volcanic ash that yields an absolute date with isotopic (radiometric) methods, like the uranium-lead or potassium-argon or carbon-14 techniques. If we have that, then we can say that a nearby fossil has a comparable age.

In the case of sidewalk stamps, we can safely assume that the numbers of the master concrete workers were assigned in numerical order. But those numbers aren’t dates. We need marks that have both a date and a master number to help establish the timeline of masters. And that won’t tell us much. A single example will only tell us that the master was active that year, not the year he earned his number or the year he retired. With enough data, we can zero in on those years but never know them for sure. I’ll see what comes up as I look around. Because as the saying goes, “What songs the Syrens sang, or what name Achilles assumed when he hid himself among women, although puzzling questions are not beyond all conjecture.”

This entry was posted on 25 March 2016 at 8:03 am and is filed under  Analysis. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.