Jump to content

Section Corners On Blm Land


HWyatt

Recommended Posts

We have been walking the BLM land near us and had great fun finding the benchmarks for the section corners and have even noted that there are benchmarks at the half way point between section corners.

 

We've been feeling pretty smug...as with the help of the gps and compass we found every corner we went for until today.

 

We took a UTM reading off our topo map. We put it in correctly into our gps that was set to the right datum....but we never found a benchmark. We got to the spot and search around in every expanding circles...but no benchmark.

 

What we wondered is if, all section corners have benchmarks.... OR, did we come up with the wrong utm...and, if there a site that we can check to see if the a benchmark has been set at this corner.

 

I read the faq's but am still confused...

 

And just in case you want more details... <_<

This particular section is in Crook County, Oregon, on the Horse Butte 1:24,000 quad. It's the corner of 6,5 & 7, 8 sectons in the NW part ((T17S?) of the map. The utm's we came up with are: 0,662,620 /4,886,930 in the datum NAD27CONUS.

 

Any help is much appreciated.

 

HWyatt

 

edit ps: We do have photos of all the other ones we have found. Most are country bm's, but some are fed government bms....

Edited by HWyatt
Link to comment

You have a couple of problems when hunting for section corners.

 

First, what they are: In some areas the original surveys which may have been done as long ago as the 1850's may have only been monumented with wood posts and referenced with pits in the ground. In some areas lines were resurveyed at a later date and newer iron post monuments were set.

 

If there is not a red + symbol on the quad it is often an indication that it is an older survey and only some of the monuments were found when USGS did it's mapping.

 

Furthermore, if it is vacant BLM land there is often no economic reason for a resurvey.

 

On private lands section and 1/4 corners (the ones you found in between section corners) may also have been found and perpetuated by other surveyors such as state, county and private surveyors since they often control the boundaries of private lands.

 

To find out what monument may be at the corner may take a trip to the local county courthouse and possibly some other agencies in that area. Again though if it is vacant BLM land there may be nothing on it except the original government surveys. The information about them is containd in field notes at the Oregon BLM office, and the locations described on plats. I believe the plats are on line, but probably not the notes.

 

The notes will describe the survey in detail, the nature of the monument set and if you are lucky accessories to the section corner. If there are trees in the area that data back to the original survey, you may find blazes, scars or even scribing on the trees. If this is a typical pinon and juniper land cover, their may be some bearing tree evidence remaining.

 

Second, where they are:

 

The old surveys are often not highly accurate and sometime even contain blunders or errors so that it is difficult to precisely determine their location. Since the quad does not show that corner specifically, and there is scant evidence of lines on the ortho photos, a surveyor would typically locate the nearest found corners in the area and compute using the latest survey records to the position and attempt to find it based on this 'search area'. Coming from different directions may yield different results.

 

Another much more complex source of information is the BLM's GCDB. This is a set of files that represent a computation of the location of all the corners based on available information. If you know the files, you can get a coordinate to searcn for and idea of the age and quality of the surveys in that area. You still do not have WHAT to search for., i.e. a wood post, mound, stone, or whatever.

 

The oregon plats can be found from this link

 

Oregon Plats

 

You are looking in T17S R15E Willamette Meridian. There is only one survey plat in there and it is:

 

Cadastral Plat

 

You will see upon examining it that it was surveyed in 1879. Pretty old stuff and anything before 1908 will not have iron post corners unless a local surveyor has perpetuated it with something. Of course there may be fence lines that go to the corners, but less likely on vacant BLM land it is possible.

 

You will also note from the plat that it is not a full mile from the west boundary of the township. It shows 73.55 chains which is 4854.3 feet or 0.9194 miles. So if you locate positions on the west line you would have to take that into account in computing where to search.

 

The GCDB for that township gives a computed position for the corner you are looking for (which their system identifies as corner id 200600)

 

200600 44 07 09.8 latitude 120 58 03.7 longitude NAD27

which can be translated to

200600 44 07 09.24 latitude 120 58 07.80 longitude NAD83

 

Actually pretty close but slightly south and west of where the topo shows it. However that is only computed position based on the old survey data and could be off also.

 

- jerry wahl

 

PS you were searching very close to the position I came up with above. But it may be hard to find without getting the notes and determining what was set and gaining experience in interpreting and recognizing those things.

Edited by jwahl
Link to comment
You have a couple of problems when hunting for section corners.

 

First, what they are: In some areas the original surveys which may have been done as long ago as the 1850's may have only been monumented with wood posts and referenced with pits in the ground. In some areas lines were resurveyed at a later date and newer iron post monuments were set.

 

If there is not a red + symbol on the quad it is often an indication that it is an older survey and only some of the monuments were found when USGS did it's mapping.

 

Furthermore, if it is vacant BLM land there is often no economic reason for a resurvey.

 

On private lands section and 1/4 corners (the ones you found in between section corners) may also have been found and perpetuated by other surveyors such as state, county and private surveyors since they often control the boundaries of private lands.

 

To find out what monument may be at the corner may take a trip to the local county courthouse and possibly some other agencies in that area. Again though if it is vacant BLM land there may be nothing on it except the original government surveys. The information about them is containd in field notes at the Oregon BLM office, and the locations described on plats. I believe the plats are on line, but probably not the notes.

 

The notes will describe the survey in detail, the nature of the monument set and if you are lucky accessories to the section corner. If there are trees in the area that data back to the original survey, you may find blazes, scars or even scribing on the trees. If this is a typical pinon and juniper land cover, their may be some bearing tree evidence remaining.

 

Second, where they are:

 

The old surveys are often not highly accurate and sometime even contain blunders or errors so that it is difficult to precisely determine their location. Since the quad does not show that corner specifically, and there is scant evidence of lines on the ortho photos, a surveyor would typically locate the nearest found corners in the area and compute using the latest survey records to the position and attempt to find it based on this 'search area'. Coming from different directions may yield different results.

 

Another much more complex source of information is the BLM's GCDB. This is a set of files that represent a computation of the location of all the corners based on available information. If you know the files, you can get a coordinate to searcn for and idea of the age and quality of the surveys in that area. You still do not have WHAT to search for., i.e. a wood post, mound, stone, or whatever.

 

The oregon plats can be found from this link

 

Oregon Plats

 

You are looking in T17S R15E Willamette Meridian. There is only one survey plat in there and it is:

 

Cadastral Plat

 

You will see upon examining it that it was surveyed in 1879. Pretty old stuff and anything before 1908 will not have iron post corners unless a local surveyor has perpetuated it with something. Of course there may be fence lines that go to the corners, but less likely on vacant BLM land it is possible.

 

You will also note from the plat that it is not a full mile from the west boundary of the township. It shows 73.55 chains which is 4854.3 feet or 0.9194 miles. So if you locate positions on the west line you would have to take that into account in computing where to search.

 

The GCDB for that township gives a computed position for the corner you are looking for (which their system identifies as corner id 200600)

 

200600 44 07 09.8 latitude 120 58 03.7 longitude NAD27

which can be translated to

200600 44 07 09.24 latitude 120 58 07.80 longitude NAD83

 

Actually pretty close but slightly south and west of where the topo shows it. However that is only computed position based on the old survey data and could be off also.

 

- jerry wahl

 

PS you were searching very close to the position I came up with above. But it may be hard to find without getting the notes and determining what was set and gaining experience in interpreting and recognizing those things.

You have answered my red + question & I didn't even ask it! Thank you.

 

This is so helpful! I'm printing off your reply for further study.

 

We did find a pile of rocks and dug around and found nothing man-made under them.

We saw a very old blaze on a nearby tree...as our search at other section corners was aided by finding the bearing trees.

 

This is mostly open range BLM, so maybe this corner has no mark. But the game is afoot, the hunt is on...our next stop will be our local BLM office as well as the websites you suggested.

 

Thank you, very much.

 

HWyatt

Link to comment

I want to add to what Jerry said towards the end of his excellent post, one small addendum.

 

I sensed that you asked if there were benchmarks on all section corners. The answer is no, there isn't, although it does happen in some cases.

 

To be most clear here, just for the essence of survey nomenclature, there are many kinds of survey marker. If you are playing Benchmark hunting here at geocaching, you are using the survey markers which are the National Spatial Reference System maintained by the National Geodetic Survey. These stations are used for locating horizontal positions and vertical elevations, monumented for the study of and working references for Geodesy. In geodetic survey terminology, the word benchmark is actually meant as two words; Bench Mark, and it means a location of Known Elevation. Only Elevation. Every other kind of survey marker which has no vertical data ascribed to it is not a Bench Mark. Geodetic Survey Markers are generally not concerned with property line survey. Sometimes the two kinds of survey meet, and it should be noted that Property Line Survey though different, is interested in the study of geodesy and how it affects PLSS. The Ideas of one are applied to the other in the thinking of the Survey industry, after all, these square miles have to fit the actual shape of the earth somehow.

 

As Jerry mentioned, when you are working with the Township and range system then that is PLSS, Property Line Survey System Maintained by the BLM. The stations set in this arena were not often as stable as the station that the geodetic surveyors set. In fact many are quite fragile. Jerry mentioned in his post that some survey markers in the PLSS system can be mounds or depressions... things you may not realize are survey markers...

 

I just wanted to draw attention to the fact that when you are on BLM land out in the middle of nearly no where looking for a survey marker, for a section corner as a for instance, the very rock pile that you dug up looking for a man made station under it may very well have been the station itself. That is to say, the pile of rocks was a man made survey station just as you found them. The old surveyors used what they had, they used the things of that day that they hoped would be lasting, and sometimes a pile of rocks to make a mound was what they used. Sometimes it is good to know what to dig for or not to dig at all.

 

So just as a side note, having the BLM Data, if you can obtain it will be good to have before you search, because that fragile pile of rocks is sometimes what you are looking for. You just never know without the data in your hand. Print out a copy of that diagram which Mike was nice enough to include here. It will give you a good idea of the distances involved in PLSS, even though the realities do not always perfectly fit the diagram. Just remember that most of those section corners have nothing to do with the game here at geocaching. You may find some will, but for the most part the stations for benchmark hunting are different all together, and they are the only stations that can be logged for credit here on geocaching.com.

 

Happy Holidays!

 

Rob

Edited by evenfall
Link to comment

More unasked questions answered. I was wondering if the term "benchmark" applied to the section corner markers (which are round and official looking.). No. Similar looking, but not the same.

 

This is all very helpful information. We are looking for the corners, not to have something to log, but to test our skills and see more country. Yesterday's hike was 5 miles of wandering thru untrailed area, in a sparse juniper forest. Beautiful country.

 

We did reassemble the pile of rocks as we found it. We will go to the BLM office and see what they say about survey marks out here. The rock pile "could" have been man made or not. Hard to tell. If it was piled up in 1880 it's had lots of time to become weathered.

 

The diagram of a section is great. In our part of Oregon sections are often talked about. We will understand them better now.

 

Jerry, Mike, and Rob thank you. Let me find out what I can and I may be back with more questions or a found survey marker. Or both. <_<

 

HWyatt

Link to comment

Bench mark

A mark on a fixed and enduring object indicating a particular elevation. It is used as a reference in topographic surveys, tidal observations, and construction.

Any object can be a Bench Mark but every object is not a Bench Mark

 

more Geodetic survey terms..

 

Closed Traverse

Starts and ends at the same point or at stations whose positions have been determined by other surveys.

 

Differential GPS

Process of measuring the differences in coordinates between two receiver points, each of which is simultaneously observing/measuring satellite code ranges and/or carrier phases from the NAVSTAR GPS constellation. Relative positioning with GPS can be performed by a static or kinematic modes.

 

Differential Leveling

The process of measuring the difference of elevation between any two points by spirit leveling.

 

Elevation

The height of an object above some reference datum.

 

Intersection

Determining the horizontal position of a point by observations from two or more points of known position. Thus measuring directions or distances that intersect at the station being located. A station whose horizontal position is located by intersection is known as an intersection station.

 

North American Datum of 1983

Adopted as the standard geodetic datum for horizontal positioning. Based on the Geodetic Reference System of 1980, the geodetic positions of this system are derived from a readjustment of survey observations throughout North America.

 

North American Vertical Datum of 1988

Adopted as the standard geodetic datum for heights.

 

Traverse

A sequence of points along which surveying measurements are made.

 

Triangulation

Determination of positions in a network by the measurement of angles between stations.

 

Trigonometric Leveling

The trigonometric determination of differences of elevation from observed vertical angles and measured distances.

 

Trilateration

Determination of positions in a network by the measurement of distances between stations using the intersection of two or more distances to a point.

Edited by elcamino
Link to comment

I took a quick look at Cadastral field notes for that township today and it describes the original corner as a stone 24x12x12. Doesn't describe any marks. It then describes 2 juniper bearing trees. 1) a juniper 10 ins. diameter, S. 32d E., 58 links distant, and 2) an 18" Juniper S. 40dW 164 links distant. There is a problem with them however.

 

In the line coming up to that section corner from the south, at the 1/4 section corner half a mile south, is a stone 24x10x8, and two bearing trees that are described exactly the same. This probably means there is a transcription error and the copiest (these are copied by hand) lost their place and copied the same two trees. That means that at one or the other I don't have a record that I can trust, and probably at the second corner, which is the one you are interested in. That's the bad news.

 

The good news is that the records I have access to are hand transcribed COPIES and it is possible that the transcription error occurred in their creation. The original set is what is in Oregon State Office Cadastral Survey BLM in Portland. There may be microfilm copies of those in a lot of local areas, and of course microfilm doesn't make such errors as long as you can read them.

 

Also there is a 1997 BLM remonumentation in the township, in particular at a lot of corners around sections 16 and 17. A remon is a survey where BLM sends out a surveyor who is able to positively identify and original corner and sets a new monument in it's place and may take new Bearing trees also. On one of these which is one mile south of yours, he notes finding the stone 'but no visible marks'. This could mean the stone is soft and weathers, or they were poorly marked or not marked at all by the original surveyor.

 

Section corner stones are usually marked with either grooves on the sides, or notches in the corners.

 

I would like to echo the caution mentioned earlier about trying not to disturb the monuments or their accessories, or as little as possible. With these older corners it can be almost like a miniature archeology site best left to methodical exploration by a surveyor who should leave behind a thorough record of what was found and what was done with it as well as an analysis of the evidence.

 

As for geocachers it can be helpful to future surveyors to document what you find and get a good coordinate on it. Digital pictures are great. At some point it might be useful to work on setting up a clearinghouse for such information, as it can definitely be useful to 1) help correct mapping such as GCDB by providing a more up to date coordinate value. 2) guiding future surveyors to the corner evidence you have found 3) helping preserve a record of such evidence as of a certain date.

 

- jlw

 

PS note a link is 1/100 of a 66 foot chain or 0.66 feet or 7.92 inches. To convert links to feet multiply by 66 and divide by 100.

Edited by jwahl
Link to comment
I took a quick look at Cadastral field notes for that township today and it describes the original corner as a stone 24x12x12. Doesn't describe any marks. It then describes 2 juniper bearing trees. There is a problem with them however.

 

In the line coming up to that section corner from the south, at the 1/4 section corner half a mile south, is a stone 24x10x8, and two bearing trees that are described exactly the same. This probably means there is a transcription error and the copiest (these are copied by hand) lost their place and copied the same two trees. That means that at one or the other I don't have a record that I can trust, and probably at the second corner, which is the one you are interested in. That's the bad news.

 

The good news is that the records I have access to are COPIES and it is possible that the transcription error occurred in their creation. The original set is what is in Oregon State Office Cadastral Survey BLM in Portland. There may be microfilm copies of those in a lot of local areas, and of course microfilm doesn't make such errors as long as you can read them.

 

Also there is also 1997 BLM remonumentation in the tonwship, in particular at a lot of corners around sections 16 and 17. A remon is a survey where BLM sends out a surveyor who is able to positively identify and original corner and sets a new monument in it's place and may take new Bearing trees also. On one of these which is one mile south of yours, he notes finding the stone 'but no visible marks'. This could mean the stone is soft and weathers, or they were poorly marked or not marked at all by the original surveyor.

 

Section corner stones are usually marked with either grooves on the sides, or notches in the corners.

 

I would like to echo the caution mentioned earlier about trying not to disturb the monuments or their accessories, or as little as possible. With these older corners it can be almost like a miniature archeology site best left to methodical exploration by a surveyor who should leave behind a thorough record of what was found and what was done with it as well as an analysis of the evidence.

 

As for geocachers it can be helpful to future surveyors to document what you find and get a good coordinate on it. Digital pictures are great. At some point it might be useful to work on setting up a clearinghouse for such information, as it can definitely be useful to 1) help correct mapping such as GCDB by providing a more up to date coordinate value. 2) guiding future surveyors to the corner evidence you have found 3) helping preserve a record of such evidence as of a certain date.

 

- jlw

Okay! Point taken about digging around in piles of rocks. We won't do it....I suspect the pile we dug in was not correct. It was a pile....of random shaped rocks and could have been Mother Nature made. We have been outta town and haven't gone out to look again.

 

We were looking for the corner of 6-5 & 7-8, north of & west of the 16-17 you mention. We are going to try again with a compass bearing from other found corners, plus reconfigure our gps based on the info that, I think, you gave us earlier.

 

Knowing what you all know, and it is formdable, and knowing how little some of the rest of us know, I wish there was an easy to find faq for BenchMark! and survey mark finding including the rule of not distrubing things. In our defense the pile of rocks we distrubed and rebuilt! looked like a pile of rocks to hold up a post....not to be a mark. BUT! we hear you telling us, ya never can tell. So piles in corners are left along from now on. :angry:

 

We did take a digital photo of it with Powell Butte in the background to help locate it.

 

Where do we go specifically to find this info. The local BLM office? Or somewhere in Portland? A silly question..but I really wouldn't know where to start to look for the records you so easily find.

 

Thanks again for all your input. We will go at it again and keep you posted on how the hunt goes.

 

HWyatt

Link to comment

Well you can try in graduated effort 1) the county courthouse, ask at the surveyors office if they have one or tax assessor or GIS dept. next. Ask if they have a copy of the BLM/GLO field note microfiche. In some states these were sent to each county, but I am not familiar with how it was done in Oregon. 2) It is possible that a local BLM office might have it. 3) the main place is here:

 

http://www.or.blm.gov/or957/cadastral/platsandnotes.asp

 

According and wander around to find a contact phone. From the one link for earlier than 1998 surveys, I see they are scanning and putting up notes also, so there is a chance, I am running a query right now. The fact that it has an entry makes me think that there may be something there, but it is taking a while to come up.

 

If I get something I'll try to get back, otherwise you can try it and see what happens.

 

- jerry

 

PS Mounds of stone are very common accessories to corners. Even if the corner itself is a stone, it is almost always set in a mound of stone, or a mound is set in reference to it, such as to the west. Of course there are a lot of other mounds that get created out there that may be from other sources.

Link to comment

Okay, wonderful, the notes are on line. I had to use IE browser to get them but at this link:

 

http://www5.or.blm.gov/lo/Notes/srvy/zNote...197OR0108001100

 

Is the opening of the notes for the subivision of the township. That is the insides of the township not the exteriors. There is usually in index in one of the next few pages ...

 

Okay here is your index diagram on page 110 using the little combo select at the top.

 

Intro p 110

 

This says that the line coming up into your sec. corner is on page 57 of this set of notes (not the volume, there are usually multiple sets of notes in a volume, this is volume 197 and page 110 of that volume...)

 

Okay I find it on page 167 of the volume being page 57 of the notes, oh neat deal I can edit the link the last digits are the page range, so this will get you the pages I want 167 and 168 becomes 01670168 at the end.

 

line between 7 and 8

 

There it is right in the middle of page 197, and that record repeats the BT's also, darned. Anyway that is what they look like.

 

Now lets see if those remon notes are in here for the corner to the south... nope.

 

Well I went over and followed the link for records after 1998 and found them here:

 

PDF of remon notes

 

You should be able to have some fun with that. I just learned a lot of neat stuff finding that on line...!! :lol::angry:

 

- jerry

Edited by jwahl
Link to comment

HWyatt,

 

In reply to your thoughts:

 

"Knowing what you all know, and it is formdable, and knowing how little some of the rest of us know, I wish there was an easy to find faq for BenchMark! and survey mark finding including the rule of not distrubing things."

 

Well, please don't feel bad. We learned it the same way anything is learned, one day at a time and what we don't know still seems formidable to us as well. Technology has us all racing to keep up!

 

I think, Looking back, many of us learned from the old school folks who were not quite as kind, patient or forthcoming with the ways of all the Ropes we had to learn... Under their watchful eyes they allowed us to make mistakes so they could show us our lessons. Call it a method of initiation or a rite of passage...

 

:-D

 

We like that you are interested. We are interested too! If you find the easy way, please share! All the Surveyors of the world will honor you!

 

Happy Holidays!

 

Rob

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...