In a thread I posted the other day about the ongoing archaeological digs for 1938 and 1940-vintage survey markers in a Central Austin subdivision, someone asked in effect how much effort a surveyor ought to put into searching for such things.
Here are photos of a couple more excavations, each with its result that provide two practical answers to the question: (1) sometimes knowing something isn't there is as valuable as knowing that it is and (2) you never know what you'll find once you start digging.
The first is an excavation that was intended to cover the entire area plus some within which several alternative theories of reconstruction might place the corner in question.
Sometimes there is a value in knowing to a reasonable certainty that nothing remains to be found. In this case, the yellow-grey clay is the native material at the site, overlaid in places with fill to various depths or some natural topsoil. This excavation extended into the clay and the bottom of the hole, 16 inches down, was carefully swept with the metal detector after temporarily removing the two recent-vintage rod and cap markers. I'm now reasonably certain that there is nothing left to find there.
In another location, the clay was close to the surface. It was a sloping hillside of that yellow-grey clay.
There was a recent-vintage rod and cap marker on the surface that fell about 1.29 ft. away from the position in which the preponderance of the evidence indicated that a pipe had most likely been set in 1940 to mark the corner. There was some background noise from a couple of old guy anchors in the ground, so I thought it was worth digging out. The excavation covered every position in which the pipe might be expected to fall, basically a trench a couple of feet long.
That actually turned up what is probably the original pipe, only now laid over nearly horizontal, probably from soil movement.
We measured the positions of the ends of the pipe to see how well they lined up with the most likely theoretical position for the corner. That point is marked by the temporary spike in the top view below. The laid over pipe is at the right of the photo.
Kent
You line of reasoning is profitable.
I believe that IF we BELIEVE that there IS evidence, that we behave differently, than if we believe that there is none.
Your posts reflect that you BELIEVED there was evidence.
Good thinking.
N
Experience
> Your posts reflect that you BELIEVED there was evidence.
Actually, I wouldn't say it was a matter of belief. It's simply a matter of long practical experience that all physical evidence of the footsteps of a survey made in 1940 is seldom completely erased.
Experience
I really enjoy your posts Kent, keep up the good work...
Experience
I think that counts as belief. We've probably all worked with people that as soon as you pull up to the job, they say something like "Oh, those pipes are all gonna be wiped out by now" or "I bet they never even set those pipes out here". That kind of attitude doesn't help in searching for monuments. Wanting it to be there and believing it's there does help.
Kent , One of the crafts of surveying that seems to have disappeared also here is how to know to continue digging and when to cease. The craft can only be learned from good experienced mentors, who fortunately never had the use of GPS and believed computed coordinates would always "fall on the spot"
It seems simple to explain but requires some astute observances of what is both above and below the existing surface level.
Here in SOZ when the era of setting and looking for metal pin offsets were the norm, if a damaged mark found by the surveyor they would lay it near the surface in a horizontal position approximately in position so as to save the next surveyor digging down !
BTW we do not have volatile soil activity where a mark could be disturbed to the extent shown in above pic.
RADU
Experience
> Wanting it to be there and believing it's there does help.
In that case, having the experience of having retraced enough of the 1940 surveyor's work previously to have formed an opinion about his monumentation practices was enough to set the shovel in motion.
Now, if you know absolutely nothing about some surveyor who indicated on his plat that he'd set iron pipes to mark the corners, the word is "presumption". Someone who wants to arbitrarily believe (possibly for reasons of their own convenience) that none actually were set would need to provide evidence to overcome the contrary presumption.
> BTW we do not have volatile soil activity where a mark could be disturbed to the extent shown in above pic.
You may count yourself lucky there. Clay soils are highly problematic for stability, particularly on slopes.
Kent, First and foremost, I enjoyed reading and looking at this thread. Generally, though for me, my search areas are in Mary's bulb garden, or Sam's pit-bull back yard. And I just can't put too much security in a horizontal pipe. My joy of the find descends proportionally with the horizontalness (new word) of the corner.
Excepting therefrom: when my final search area is larger than the length of the horizontal pipe and no grading was ever done in the area.
> And I just can't put too much security in a horizontal pipe. My joy of the find descends proportionally with the horizontalness (new word) of the corner.
Yes, that's true that only in the rare case (where the marker was originally set horizontal, as in the face of a near-vertical surface) is a horizontal marker much help. In this case, though, the pipe looked like this:
The downhill-pointing end (seen at the right above) still had traces of galvanizing on it, but the uphill, lower end was well corroded. The interpretation that made sense to me was that the downhill end had not spent much time below grade during the life of the marker. That was consistent with a pipe that had been set with the top inch or so above grade and that had then crept downhill with the clay soil over 70 years.
So, if that had happened, where did the marker start out? Can't say, but it seems reasonable to me that the original position would fall in plan projection approximately along the extension of the axis of the pipe as found.
Experience
> > Wanting it to be there and believing it's there does help.
>
> In that case, having the experience of having retraced enough of the 1940 surveyor's work previously to have formed an opinion about his monumentation practices was enough to set the shovel in motion.
>
> Now, if you know absolutely nothing about some surveyor who indicated on his plat that he'd set iron pipes to mark the corners, the word is "presumption". Someone who wants to arbitrarily believe (possibly for reasons of their own convenience) that none actually were set would need to provide evidence to overcome the contrary presumption.
Ding ding ding! We have a winner. Sadly corner search is a withering skill in our profession these days. The numerous examples of pin cushions nationwide prove it.
Experience
> Sadly corner search is a withering skill in our profession these days. The numerous examples of pin cushions nationwide prove it.
In the example of these two subdivisions, I think that the common theme is that the work is being done by remote control with the licensee who is in theory responsible for it sitting in the office trying to keep several field parties in motion on residential lot surveys that were taken on for some ridiculously low fees. The modus operandi of the surveyor of record is apparently to maintain plausible deniability, i.e. to insulate himself or herself so that the excuse is that the ultimate failure of the effort was due to some low-pay, low-skill employee not following his or her instructions.
Experience
I fear that of which you speak has potential to become more commonplace.
Neglecting corner search shows obvious lack of respect for the license, the public and the profession.
We are all human and as such susceptible to mistakes (missing evidence), but a pattern of not even searching for original corners is abhorrent.
Even after I have searched at length for corners I always take one last look before setting a new monument.
Experience
> Even after I have searched at length for corners I always take one last look before setting a new monument.
That is a highly commendable practice. There will be mistakes, but seldom and of little consequence are the targets.
Experience
Experience
Hmmm. Well, finding old evidence in my view is pretty much basic competence - and basic competence isn't exactly showboating. What experience brings is a constant alertness to what has yet to be found or disclosed, the small clues that unravel the mystery.
At least one shovel-full more than the last guy that looked. Now go find those buried
stones:) As a sidenote, I have also found a number of buried and formerly lost buried
stones that have been resting comfortably for years in the company of newer iron pins
set as its corner replacement. Not by luck but by perseverence. Sometimes returning to a job 3 4 or 5 times.
My rule is to search to the extent that no one else will ever find anything I might have missed.
Hopefully you'll reset the pipe found disturbed where it was supposed to have been and note it so on your plat.
We find corners all the time that we "rehabilitate" either laying close to prone or just bent. Some are easier than others.
In your case, it appears "pushed" so you can determine which one was actually driven in either from corrosion or some form of mushrooming to the head. It's when you can't determine that fact that you end up having to back up ten and punt.
Either way, good find. My metal locator will pick up those pipes and rods deep also. It's a wonder the other guy didn't find it. OTOH, it's possible that he did, called it destroyed, and set his corner based on other evidence. If this is the case, you really can't fault the guy, but it should tell you so in the dirt when excavating the pipe.
> Hopefully you'll reset the pipe found disturbed where it was supposed to have been and note it so on your plat.
You can't be serious. The pipe only shows a general line along which it was originally placed. It would be very poor practice to manufacture evidence by resetting the original. This corner will get a new monument.