Government Shutdown Affects NGS, USGS

Due to the government shutdown, the NGS and USGS websites are currently unavailable.

Archived NGS datasheets (from 2000-2001) are available at

These are useful only for benchmark hunters and are not to be considered reliable survey data.

Some USGS datasheets are available here:

NOAA’s Tides and Currents website is still active. Tidal bench mark datasheets are available here:

Local agencies’ marks may be available here:

Benchmark Interview

August 15, 2006: The following questions were posed by Angus Stocking, editor of the upcoming book Lasting Impressions: A glimpse into the legacy of surveying, in which several of my benchmark photographs and stories are to be published. I am sure the entire “interview” won’t be used in the book; I think it was simply intended to give Angus enough background information to write a short paragraph about me. But after writing it I could see the value in posting it on my site, both to satisfy the curiosity of some of my regular visitors, and possibly to spark some interest in those just passing through.

How did you get into benchmark recovery, and how long have you been doing it?

I first became aware of benchmarks in January 2002 through a now-defunct geocache called the NGS Benchmark Recovery Cache. I went out that afternoon and found my first mark, a triangulation station called SOUTHSIDE, not more than a mile from where I was living at the time. It wasn’t until several months later that the Benchmark Hunting section of went online, but once it did, I was hooked. And I already had found several more marks in the meantime. From the beginning, I was interested in learning how I could contribute to NGS, and I was pleased to find that they welcome and value my observations. I have currently submitted to their database well over 100 official recovery notes.

What are your motivations?

First and foremost, I’m motivated by discovering the connections these marks give me to surveyors and all others who may have seen them and worked with them through the decades. Investigating these marks takes research, patience, and an eye for the little clues that remain long after the most obvious structures and pathways become victims of time and progress. I am also inspired by the fact that I can contribute to the ever-growing NGS database and that my words and measurements will be useful for years in the future. I also have personal motivations. Benchmark hunting has pushed me to climb to mountain summits with beautiful vistas and creep into hidden city corners I never would have seen otherwise, has introduced me to Monica Lewinsky’s apartment building and C. S. Peirce’s estate, has encouraged me to hike along the Appalachian Trail and the Long Path. I’ve become somewhat a collector of experiences, and my memories, stories and digital photos are more precious than any tangible souvenir. I’ve developed my photography, writing and map-reading skills; have researched old buildings, abandoned streets and rail lines; and have improved my physical health.

What are your goals re: benchmark recovery?

I intend to continue searching for and documenting marks for a long time to come. I aim to maintain a high level of care in documenting the marks I find, so that my entries into the NGS database will continue to be of value to professionals. I have kept full photographic documentation of each mark I’ve found and intend to submit these photos to the database as well, when provisions are made for such entries.

About how many benchmarks would you say you’ve recovered?

My current count is 315, which in addition to simple elevation benchmarks includes marks I’ve demonstrated to be destroyed, as well as triangulation stations (whose auxiliary marks I do not count separately unless they have their own PIDs). I don’t go for the quick finds and big numbers like some “hobbyist” hunters do. I prefer to take my time and do a complete recovery, as well as to seek out some of the more obscure marks. Marks that are not found often require more work than the marks that are easy finds, but they aren’t included in our totals. For various reasons not all marks I find are reported to NGS, the most common of which being that many marks are USGS-only, or there have been no changes to the marks’ descriptions or status in the past year.

What are some notable experiences you’ve had?

The stories are lengthy, but just for some examples: I’ve found marks with errors in their descriptions or measurements, which I was able to note to NGS. I’ve met people who were on-site when triangulation stations were set on their property, and who were all too happy to help me with my own recoveries. I’ve found a bolt set in 1865 which is still in great condition today. I’ve also been challenged, chased away from highway shoulders, and watched with suspicion. Probably the best experiences I’ve had have been when I use the clues I find at the site and the old recovery notes to piece together where a tricky mark must be located, and then poke around in the dirt or shrubbery, and actually find it!

And just for background, what’s your day job, and what are some of your other interests?

I work as a computer systems technician and programmer for an academic library. My main interests are website development, railroads and trolleys, photography, local history, and many outdoor pursuits (hiking, mountain biking, hunting, rock climbing).

Chocolate Benchmarks

Why chocolate benchmarks? While browsing web sites last year I came across some silicone molding compounds that I thought would be fun to play with. I wasn’t sure what to use them for, but it occurred to me that it might be fun to make molds of benchmarks, and then create chocolate treats.

Then I started thinking (as did others around the same time, as evidenced by this forum thread) that a similar process could be used to make a mold of a mark still in its setting if there was something special about it. (Or if you’re really into it and have a lot of spare time, I suppose you could make a mold of every mark you find and start a collection.) Here is the process I used to create my chocolate benchmarks.

1. Find a Benchmark

Unused gaging station disk
Unused gaging station disk

This may be the hardest part! I happen to have quite a few survey mark disks of various types, most of which are unused disks I acquired from surveyors or others in related fields. One was a Destroyed mark that had to be removed from its setting. I also have several 1-inch replica pins such as can be ordered through You may even want to modify the process and capture impressions of marks in the field.

The disk I’m using for my demonstration was never used in the field. It was sent to me by a USGS employee with whom I’ve corresponded on an urban exploration forum.

Make sure the disk is clean before making the mold.

2. Make the Mold

Jars of silicone molding material.
Jars of silicone molding material.
Possible molding materials abound, depending on how much time you have to make the mold, what you plan to do with it, and how long you’d like to keep it.

I chose Culinart’s Silicone Plastique, a food-safe silicone molding compound, because I planned to use the molds for edibles. I also liked the fact that the silicone will produce flexible molds that are heat- and cold-resistant.

a. Measure the molding compound

It's almost like baking.
It’s almost like baking.
For this four-inch disk, I used approximately 2.5 tablespoons of each component. The catalyst (blue) and base (dull white) need to be mixed in equal parts.

b. Mix it together

This still needs to be mixed and kneaded some more.
This still needs to be mixed and kneaded some more.
The components need to be mixed until a uniform light-blue color is reached. I do this slowly so I don’t introduce too much air into the mixture. Once the two are mixed, you’ve got about twenty minutes to work and an hour until the silicone fully cures. It’s sticky, so I lined the board with waxed paper.

c. Fill in the details

Spreading on a thin layer.
Spreading on a thin layer.
It’s best if you fill in the fine details first with a thin layer. Be sure not to trap air bubbles beneath the silicone.

An offset spatula might help, or just use your fingers.

d. Complete the mold

Smooth up the sides.
Smooth up the sides.
Form a 1/4-inch thick patty from the remainder of the silicone and press the mark down into it. Then smooth the sides of the mold up to conform to the edges of the mark.

The finished mold.
The finished mold.
Let it sit for at least an hour for the silicone to cure, then peel away the mold. (Test it first by trying to press a fingernail into the outer edge of the mold, just to make sure it has solidified.)

3. Make the Chocolates

a. Melt the chocolate

For the best look and taste, buy real chocolate and learn how to temper it. Did I do this? No, at least not yet. I used quick-melting candy wafers that are available in most arts & crafts stores.

If you’re using candy wafers, just follow the manufacturer’s directions. Generally they’ll melt in a few seconds in the microwave. Or if, like me, you don’t have one of those newfangled contraptions, they’ll melt equally well in a double boiler. And if, like me, you don’t have a real double boiler, you can make one out of a shallow metal bowl set atop a deep pot half-filled with simmering water. You’ll figure it out.

b. Fill the mold

Filled mold
Filled mold

Pour the melted chocolate slowly into the mold. Lifting the mold a few inches and dropping it on the counter several times will help release any air bubbles that may have formed.

As you can see, some chocolate spilled over the sides. It’s very easy to remove the excess after the chocolate hardens.

c. Chill and unmold

The finished disk!
The finished disk!
Refrigerate 20-30 minutes or until chocolate has hardened, and then pop out your chocolate benchmark! They go very well with tea and shortbread cookies.