I am following an 1875 Deputy around a township. We are using the best available evidence to restore corners. Fortunately there is an early 1980s BLM Dependant Resurvey which retraced about half the Township and a lot of corners have been perpetuated by Timber Company personnel through time too (the Township was subdivided in 1875). The Timber Company corners can be verified by original accessories but there has been considerable fading of the evidence since the early 1980s. Finding a Timber Company perpetuation carries a lot of credibility (even if the accessories have been recently destroyed due to timber harvest activity) due to BLM being able to verify much of their work earlier if that makes sense.
This 1875 Deputy seems to have been able to measure miles to an accuracy on the order of ±10' (in moderate rolling terrain). His directional accuracy is a little rougher, maybe on the order of ±20' in the mile. In one Section the quarter corners are each about 15' off-line. I didn't really expect distances to be more accurate than directions but on the other hand given the way they ran lines by short sights and offsetting around trees, etc it would be expected that they would wander somewhat back and forth. One line with a very steep and deep canyon he was 14' off my measurement; that's amazing in my opinion. Maybe they snuck some better methods such as stadia or triangulating to a baseline on the other side of the canyon.
In California it seems like the best GLO work is in the middle to upper Sierra Nevada Mountains. There is some really wild stuff in the Coast Ranges (like Sections skewed off cardinal 1000' in some cases).
Dave, who is the deputy you're describing?
I'm particularly curious about GLO work in CA pre-Benson era. Particularly in the N. Sierra, S. Cascade areas.
As for timber company perpetuations, buyer beware. I worked in one area last year that I found a few corners that were clearly poor attempts at reestablishments of positions by some Kimberly-Clark forestors sometime around the 1970's. Long story short, let's just say they didn't always perform due diligence in evaluating evidence before building a mound of stone.
Well everything is buyer beware; I mean you work with what you have got.
The Deputy's name is William L. McKim. 1873 to 1875. There are just too many cases of there happens to be the right trees at the right bearings and distances from the corners to say it is a coincidence. BLM also found some of the 3x3 posts he set. Unfortunately sometimes he didn't build a stone mound because there was no stones around nearby.
I am certain he was there and he did what he said he did. You find a corner with evidence of accessories which fit. OK that could be a coincidence. I could probably wander around the forest and eventually find a set of trees which fit the notes. But finding that in about the right location and with 4 other found corners each way that also happen to have the right pattern of trees and close to record bearing and distance is more than just a coincidence. In a few cases they came upon a pipe in a stone mound with evidence of accessories nearby (the black oaks don't make a good record of scribing and the conifers have all been harvested so you have rotted blazes or a stump if you are lucky). I suppose they could ignore it (anyone can build a stone mound) and double proportion but that doesn't seem like a good solution either.
I agree however if something is just way out of wack or you can find better evidence then you should use it.
yep,
just makes it tougher when you find evidence that someone who has widespread holdings (timber company's forestor) has been making mounds of stone somewhat willy-nilly.
> I could probably wander around the forest and eventually find a set of trees which fit the notes. But finding that in about the right location and with 4 other found corners each way that also happen to have the right pattern of trees and close to record bearing and distance is more than just a coincidence.
In fact, you can do probability analysis that shows just how unlikely finding a particular pattern of evidence is. The odds that it is just a random occurence can be quite small when the average distance between trees of eligible size and species gets large enough.
> In fact, you can do probability analysis that shows just how unlikely finding a particular pattern of evidence is. The odds that it is just a random occurence can be quite small when the average distance between trees of eligible size and species gets large enough.
Dang Kent,
I found the particular pattern in your random occurence...even with a forgotten R...;-)
Ra oyql, zpv qya sp bxpeyercrlz yayczfrf luyl fuptf hvfl upt vacrgicz orasrad y byxlrqvcyx byllixa po ijrsiaqi rf. Lui pssf luyl rl rf hvfl y xyaspn pqqvxxiaqi qya ei wvrli fnycc tuia lui yjixydi srflyaqi eiltiia lxiif po icrdreci frmi yas fbiqrif dilf cyxdi iapvdu. -Gial NqNrccrya
DDSM;-) :beer:
(occurrence)
If you send an infinite number of monkeys into the township one of them will find all of the original corners, right?
> If you send an infinite number of monkeys into the township one of them will find all of the original corners, right?
The first thing one needs to work out is the average density of eligible BTs in an area. I work the problem like a game of Battleship, dividing the area into small enough squares that any evidence of BT remains within the square would be considered to be a hit. In Texas, a grid of squares 2.5 ft. x 2.5 ft. would be reasonable for many retracements since the original ties often weren't made any closer than that.
If the average density is, say, 4 per acre in an area, then the chance of a BT being in any particular 2.5' x 2.5' square would be 1:1742 or 0.000574. That means that, in that situation, for any particular tree that could possibly be the remains of a BT, the chance of another randomly distributed tree lying at the record course and distance from the one found is 0.000574. By the time you work the conjugate probability for several corners, the odds are usually really, really small that you're looking at a random event.
No,but if you give an infinite number of idiots a keyboard they will monkey around and found the internet.
Not So Sure The Monkeys Would Recognize Evidence
Bananas yes, reference marks and monuments no.
Paul in PA
10 feet?....20 feet?.....
Dag gummit, Karoly, you can set those corners better than that. Now, forget about retracement, comp the corners in the "right" position, and fire up the GPS! You need to do it RIGHT!