Searching For An Old Mark....

[+Old Bill]

Hello all, and Happy July 4th!

 

I've got quite a wish list of old benchmarks that I'd like to go looking for, and this leads me to some questions....

 

First, how far off can one expect the coordinates to be for benchmarks from the 1850's? 1900's? 1935?, etc, etc. In particular, some of the areas I'll be searching may very likely have none of the features listed in the "get to" directions, so I'll be probably having to canvas an area based on the given coordinates to find it.

 

Second, can anyone suggest a good way to cover an area looking for these older marks? Things like how to search, what to look for, tools/gadgets/gizmos to have etc, etc, would be very helpful.

 

And a bonus question...Is there a website that explains (in layman's terms) exactly what we are seeing when we find a "triangluation station", a "reference mark", an "azimuth mark", and so on, and how they interact with one another, etc? Or possibly, would any of the pros here care to give a quick guide to these things?

 

I apologize if this has been covered before, I couldn't find specific answers to these.

Links are as appreciated as answers.

 

Thanks! This forum is great!

[holograph]

Old Bill,

 

It's important to look at the NGS datasheet to see how accurate you might expect the coordinates to be. It will say either "SCALED" or "ADJUSTED". The scaled coordinates can be off by a large amount, by hundreds and sometimes thousands of feet, although often they seem to be off by about 150 feet or less. Adjusted coordinates will be accurate to better precision than your GPS receiver.

 

If you have scaled coordinates, then you have to use the description and your powers of observation -- that's what makes it fun, since every search can be a historical puzzle to solve. If you are looking for disks, then a metal detector can be useful, but it's not necessary. A few poeple here don't even use GPS receivers and prefer to use only the directions on the datasheet.

 

There was a recent thread (here) that contained a few explanations of some of the terms you are asking about.

[+Spoo]

As for looking......Yes, Get all the NGS sheets you can. I also recommend the Topo downloads as this will often show a deviation between where the surveyor thinks it was and where the co-ordinates think it is.

 

Heading off anywheres, especially mountain tops or deep forests, you cannot have enough documentaion. If the directions listed are long straight lines, I recommend a second person to help.

 

In this neck of the woods, items mounted in open ledge or on large boulders are generally easily found but can often be under 1 inch of dirt/mud or 1-3 inches of moss. Be prepared to get dirty. Carry a rag to clean off the item for photos.

 

If the item is mounted in a concrete monument or boulder or ledge AT GROUND LEVEL, I often expect to find them buried. Even early-mid 1970 disks around here are 1-3 inches beneath the surface. Have your probe, entrenching tool (or if rich, your metal detector) handy.

 

NOTE: This concept of marks from even 1976 being under three inches of soil bothers me. Is the world getting larger? Or do some of you in some other location find the monuments 'rising' higher out of the ground? Where is this excess dirt coming from ? lol

[+Black Dog Trackers]

Old Bill -

 

Although you didn't ask it directly, here is an old topic on how to find old marks. I think you probably already know this stuff, though.

 

Yes, the to-reach directions on very old marks are often of no use. Fortunately, many older marks are location-ADJUSTED marks, so they can be found with a GPS. The SCALED ones are likely hopeless unless 1) surveyors are currently using it and have marked it or 2) you can find it with a metal detector if the mark is metal.

 

Gizmos: metal probe, metal detector. I've never used a metal detector to find benchmarks but I have found several marks with a simple stiff wife probe that I keep folded in half in my pack. Mloser has an excellent probe he made from a long barbecue fork.

 

What to look for: a pile of rocks, a witness post, colored flagging hanging in a tree, a depression in the ground, bare rock.

 

As to the bonus question, the simple version is that triangulation stations have a triangle in their center, vertical control (true benchmarks) and other survey stations have a horizontal line across the disk with a very short vertical line in the center, reference marks and azimuth marks have a horizontal arrow across the center. Reference marks typically say "REFERENCE MARK" around the rim, and azimuth marks say "AZIMUTH MARK". You can view generalized diagrams of these marks on Dustyjacket's site by clicking on the two links for "Diagrams of different Survey Markers". His site also has a good collection of photographs of different types of marks! Of course, the good ol' Benchmark Gallery is a worthwhile way to get experience at what marks look like.

[2oldfarts (the rockhounders)]

Thad/Old Bill,

 

This old mark with a large rock cairn is adjusted...have a peek...DU2273.

 

It might prove fun to try for this one & some of the other ones we listed here , that you can drive close to, just to see if you could spot those rock cairns. You should be able to see them on the horizon in the general direction long before you arrive at the "Adjusted" coordinates!

 

Here, in the AZ. desert, we are extremely lucky, because the old directions are fun to read & sometimes contain info that is still usable...as in 'ranches' are now old abandoned cabins, or at least old corrals. The term 'pack' means the time that it would take a person who is in shape & in the cooler times of the day or year. Adjust that time according to conditions of both weather & season, plus your physical condition. If you get lucky, there will be a jeep trail leading right to the mark now.

 

Even a few very interesting marks have caches that are close to them, because of the beautiful vistas. You have remember, as one of our learned members once told me, the reason you have such fantastic views from the placement of the mark, is due to the ability of sighting from one mark to another.

 

At those old marks you might just get to see some of the wooden structures used to hold the survey equipment as we found here. It was at a triangulation station. It also had the wires attached to the spikes in the ground (sometimes tied to the surrounding rocks).

 

The marks that you really have to hunt for are the chiseled marks & drill holes. Even if they are adjusted...the sand tends to blow & fill these marks in around here. It just takes a little extra time & effort, but worth every bit of it when you are able to find them.

 

Trust us - it will not take many marks at all until you are answering questions yourself.

 

Enjoy the hobby!

 

Shirley~

[2oldfarts (the rockhounders)]

Old Bill,

 

2 things that have not been mentioned, but can help your recovery rate are old maps and high places.

 

Old maps (that were made a few years after the mark was set.) show a lot of roads and terrain that modern maps don't have. They also show where a road used to run before it was re-routed, and sometimes old buildings are also shown.

 

As for high places, These can help locate old raods and trails. It takes a little practice to be able to spot where an old wagon trail or early dirt roads meandered across the landscape. Sometimes, the only give-a-way is the growth pattern of certain weeds. Then upon closer inspection you can find other details to help verify that it is the road you want.

 

The final thing that can really payoff is Just Plain Luck...

 

John

[+Old Bill]

Old maps (that were made a few years after the mark was set.) show a lot of roads and terrain that modern maps don't have. They also show where a road used to run before it was re-routed, and sometimes old buildings are also shown.

Any recommendations for where to find old maps? Mostly 30's and 40's in the Southern part of AZ is what I'm finding.

 

Thanks for the advice....

[ArtMan]

I'm afraid it won't help in Arizona, but Maptech has historical topo maps for a number of states including Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, and West Virginia. Coverage is inconsistent, but can be enormously helpful if you are lucky enough to find a map (usually 15 minute) for the area and epoch you're searching.

 

-ArtMan-

[2oldfarts (the rockhounders)]

Old maps (that were made a few years after the mark was set.) show a lot of roads and terrain that modern maps don't have. They also show where a road used to run before it was re-routed, and sometimes old buildings are also shown.

Any recommendations for where to find old maps? Mostly 30's and 40's in the Southern part of AZ is what I'm finding.

 

Thanks for the advice....

 

Old Bill,

 

We've found most of ours by accident. In old Ghost town books, yard sales, library sales. USGS district offices, where they copied some of their old maps for us, since they didn't have any for sell. Rockhounding sources including stores and universities (I think 1 was in Salt Lake City,UT and one was Reno, NV. Check with the Division of Mines & natural resources for state and/or county maps.

 

Hopefully Geo-Trailblazer will share some of his sources.

 

John

[Difficult Run]

I've had great success finding old maps at the local library. The Fairfax County Regional Library has a room for history and genealogical work, named the Virginia Room. They have copies of maps for Virginia dating back to the early 1600's. Also, they have original maps USGS maps for nearly every county in the state, some dating back to 1915.

 

My suggestion would be for you to check your local library system, and the local historical society for map documentation. Don't forget the county survey office. Also, the Library of Congress has some maps online, (way cool).

 

Just a little off topic, but I'd love to see more and more maps in digital format, ie., scanned in to .jpg or tiff files. It would be a blast to overlay these maps with present day ones to see how the roads and communities have changed.

 

We will get there over time though.

 

Once in the field, use the previous recovery notes and mentally place yourself back in time. The first thing I often do when arriving is to close my eyes and picture the site as it used to be. Look for things that don't change over time.

 

Good luck

- Mitch -

[holograph]

There are a couple of online antique map collections. There is the David Rumsey Collection, the Perry-Castañeda collection, and the Alexandria Digital Library, in addition to the Smithsonian collection.

 

Some the the old Railroad maps in Texas are particularly interesting, because they show how much the railroads influenced the land development. I was curious one time about why the modern day roads and political boundaries in parts of Texas seemed to be on a grid set an a nearly a 45-degree angle to the standard PLSS system. It turned out that a large railroad grant cut from northeastern Texas over to the panhande at that angle, and all the land was surveyed perpendicular to the railroad grant, leading to the cockeyed grid system.

[+chaosmanor]

One very valuable "tool" that hasn't been mentioned directly so far, but which is implied, is PATIENCE. Lots of it, sometimes. Sometimes, you can read the Description, find most of what is mentioned in it, and even find the disk, square, tack, whatever, but the measurements are so far off as to make you wonder how many drinks the guy who wrote it up had when he was in the field. Some marks have been recovered often, but are still missing, due to sudden changes. I've seen marks disappear between two visits a month apart, due to construction. Highway widening can destroy a whole string of disks. And, as mentioned, dirt, leaves, etc. can build up over time and completely cover a disk. This is particularly true along shores and in farm country, but it can happen anywhere.

 

But having patience can help you solve the puzzle! Sometimes, the story that unfolds is really interesting, if only to someone like us. Don't be surprised if you need more than one trip, too. I've got one disk along the ocean, near Malibu, that I've made three trips for, and I still can't find it. Got one of the Reference Disks, got most of the landmarks, but haven't dug down far enough through years of sand buildup to get that disk. I'm 98% certain it's down there. One of these days, I'll either get it, or prove that it isn't there.

 

Have fun, most of all. This is a game for most of us. If we file good Recoveries, we're doing the public a service, and I'm proud and happy to be a very small part of a worthwhile effort. But, at rock bottom, this is a game, a puzzle to be solved. If you aren't having fun, you shouldn't be bothering.

 

Good luck in all your hunts!