BenchmarkHunter

Mine shows 1305 finds. Profile page, then click on Benchmarks, and choose the option I want - All, Found, etc. But I maintain my own Access database for this, can create reports of my activity, and I can include partial finds, like finding a reference mark, but no main disk. And my database uses datasheets that I downloaded in 2014, so it has a few additional marks that aren't here. So, my "true" count is 1326. Of those 477 are "disks," and the remainder are survey rods, intersection stations, landmarks, etc.

Surprised nobody else posted this - BUTTERMILK, aka LX4113, a drill hole from 1833, and some of its reference/azimuth marks. I've found disks from around 1900, e.g. KU0584, otherwise called "74," which was set in 1901, and was my 500th benchmark find. There's another disk nearby, called "37" (KU1581) that has to be contemporary with "74." And my "picture" is the 1903 disk called FOREST PARK, KU3315, which was set in 1903 and is the last surviving disk from the 1903 survey of New York City.

I got into benchmark hunting when we went on a family vacation to Gettysburg in 1970. My login handle says it all . For me, it's learning about the local geography and when/why benchmarks were monumented. I live in NYC and also have our 1909 survey of well over 1000 benchmarks, a small number of which are in the federal database - many of those have been destroyed as NYC has changed, but quite a few still exist. It's quite a thrill to find disks that have been in place for more than a century. Someone mentioned Buttermilk - that mark was set in 1833, by Ferdinand Hasslar, the first head of the Coast and Geodetic Survey, appointed by Thomas Jefferson. Nice American history trivia. I've been out of benchmark hunting for a few years, but have been bitten by the benchmark bug, again, and hope to resume enjoying my hobby. And, yes, FTFs are fun.

I've sometimes used "Not Found" to mean "likely still there, but you're not going to see it." Example - paved over in a parking lot, where it's obvious that a new layer of blacktop was put over the old, rather than excavating the old surface (which would have made the mark "Destroyed"). I'm very cautious about "destroyed" reports because those could well discourage anyone from looking for the mark in the future. Just because I didn't find it doesn't mean that it's destroyed, unless, as stated, there's irrefutable evidence that the mark is gone. If there's any evidence of the mark, it's definite not "destroyed" and not "Not Found." I use "Fair" for a mark that's identifiable, but severely battered, or gooped over with layers of paint obscuring the markings (except where someone scratched out the stampings), etc. For me, "Poor" would be things like - a diskless stem, or a mark severely leaning and accuracy compromised. I always research a little about "Not Found" reports because it's not unusual, even on an NGS datasheet, to see several "Not Found" reports followed by a recovery. That said, it's a common mistake to mark something like a water tank as recovered, when the tank is clearly not the one described on the datasheet. Another mistake is when a benchmark is reset, often because the original mark has been destroyed (though the original could still exist, perhaps disturbed), and someone didn't look at the full description or the complete stampings.

Thank you for your kind words. In some regards, it is remarkable that any of the Koop marks still exists in Queens, and a 10% success rate is probably pretty good, indicating the extensive construction and destruction that has happened throughout the Borough in the last century. A few of the "Not Found" marks are likely to exist, but are covered or, in a few cases, on a building to which I cannot get access, e.g. a subway power station in Rockaway. I have not explored Staten Island, yet, but I have done some work in Brooklyn, Manhattan and The Bronx, and have been running about a 30% success rate in those Boroughs, though, so far, I've been looking for marks that I was more likely to find. For me, the most interesting - and most challenging - aspect of the Queens recoveries was to translate the Koop pre-1915 street names into their modern equivalents, which is a task that I have not had to do, for the most part, in those other three Boroughs. And it's always a thrill to find a mark that's not on a school, church or bridge, like the one on the old trolley depot and waiting room on Northern Boulevard - trolley service started there in the 1890s, part of the depot burned in 1930, the depot was abandoned for decades when Queens trolley service from that depot ended in the late 1930s, and finally it was renovated in 1987 into the Tower Square shopping center. But the Koop chiseled square is still on a bluestone windowsill, where it's been for more than 100 years.

I posted my notes, below, in a recovery entry for KU1416, but figured that I might get more responses here. For background, marks A USE (not in the NGS Database) and B USE (KU1416) are on the Queensboro Bridge, on columns on opposite sides of First Avenue at 59th Street in Manhattan. There is also a chiseled square, 1670 BOM (KU1415), which I found on the west column. The A and B marks are unusual - two inverted "Y"s whose stems intersect at about a right angle, forming an approximate square that's open at one corner. Of the two USE marks that were set, I found the one on the west side of 1st Avenue, which looks like it should be the A mark from the original documentation for this mark provided by Papa-BearNYC in his very thorough notes for KU1416. There is absolutely no trace of the B mark on the corresponding column on the east side of the street, which is why I've submitted this post. Given that the two marks were made at the same time, on the same material, in the same location, and that neither mark was protected from the elements more than the other, I'm surprised that the A mark would still be easily visible, while the B mark would have disappeared without a trace. Both marks would have been high enough off of the ground that they were not likely to have been destroyed by human action, and it would have been unlikely that, over the years, one mark would have been selectively destroyed while one would survive. I've seen marks chiseled in bluestone that have disappeared over a century, but granite should be much more durable. It's also curious that the NGS datasheet coordinates for the B mark are identical to those of 1670 BOM (KU1415) which is on the west column, with both marks having coordinates listed on their NGS datasheets to the tenth of a second, which is about 10 feet. The east column is much more than 10 feet away from the west column, so if the B mark were on the east column, it should have coordinates that are a little different from those of 1670 BOM. The A and B benchmarks also have the identical elevation to 1/100 of a foot - 1/8 of an inch - in their original description. Is it possible that there was only one mark established, even though there are two entries in the original description? That would explain why only one mark was included in the NGS database. Or, is it possible that the marks were accidentally "switched at birth," with B actually on the west column, not the east column? Mistakes in a mark's original description, though rare, do happen on occasion. I hope that my question/concern is clear. If not, I can clarify in a follow-up post. Any information that can help to resolve this puzzle would be very much appreciated. Thanks.

Very nice reminiscences, Harry. I am a native of Queens, and, without giving away my age , I was a child when the 1964 World's Fair opened and I grew up close to the Fair and went there almost every weekend. Much of Queens's post-Koop development happened before my lifetime, but I can remember some new construction in eastern Queens in the 1960s. It is a sad commentary that only about 10% of Koop's 233 benchmarks have survived in Queens, most of which are on schools, at Fort Totten, or on a couple of bridges. For this Koop benchmark project, I have thoroughly enjoyed researching 1909 Queens and translating the street names and road rights of way. I now have a much better understanding of the evolution of my home borough over the past 100 years, and I look forward to learning much more about the other 4 NYC boroughs, as well.

Over the past 18 months I have endeavored to visit the locations of all 233 benchmarks set in Queens County between 1909 and 1914 by the Frederick Koop team. This has been a very time consuming project for two reasons. First, the Koop report talks in terms of street names in 1914, and the vast majority of Queens streets were renamed to their modern designations between 1915 and 1925. Second, Queens of 1915 was mostly small villages connected by a few main roads, with lots of farms and large estates throughout the County. Most of those farms and estates are long gone. Some streets no longer exist, or the right of way has been split to form several connecting streets. I was fortunate to have found a complete set of old-to-new street designations, and to have found a 1909 Insurance Map for all of Queens County so that I could match up old and new streets. Of the 233 benchmarks set in Queens County, I have been able to visit 231, and find only 22, five of which are in the NGS database. Two more benchmarks (737 which is in the NGS database and 734 which is not) require access to the seawall in Fort Totten, behind a restricted NYPD area, and I'm trying to see whether I can get access to them. They're likely to exist, bringing the Found total to 24. Here are the ones that I have Found and photographed, with their modern locations: 537 - KU1325 - a copper bolt at the Fire Department Building in Lawrence, Nassau County 575 - a chiseled square on PS64 in Woodhaven 580 - a copper bolt on an abandoned LIRR Power Station at Atlantic Avenue and 99th Street 589 - a chiseled square on PS34 along Springfield Boulevard 590 - KU1193 - a copper bolt on PS34 along Springfield Boulevard 593 - a chiseled square on the main entrance of PS33 at 222nd Street and 92nd Road 607 - a copper bolt on the school at 88-02 144th Street, Jamaica 616 - a chiseled square on PS68 in Glendale 617 - a copper bolt on PS68 in Glendale 636 - a chiseled square on the Borden Avenue Bridge 653 - a brass tablet (the only tablet surviving in Queens) on the school at 85-28 Britton Avenue, Elmhurst 654 - a copper bolt at the 23rd Street underpass of the Queensboro Bridge 655 - a chiseled square at the 23rd Street underpass of the Queensboro Bridge 660 - a chiseled square on the window of the old RR Depot at Northern Boulevard and 52nd Street 664 - a city monument at the corner of Vernon Boulevard and Broadway 672 - a copper bolt on PS84 in Astoria 673 - a chiseled cross on PS84 in Astoria 674 - a chiseled square on a bricked up window's sill at 21st Avenue and Steinway Street 721 - KU1110 - a chiseled square on a building at 110th Street and 15th Avenue in College Point 729 - a copper bolt, plastered over but obvious, on PS79 in Whitestone. Call this one a "diskless stem." 735 - KU0979 - a chiseled cross on building 615 in Fort Totten 736 - KU0976 - a copper bolt on building 637 in Fort Totten Mark 709 (KU1136) on the Little Neck train station building is no longer visible under even more paint than before. I have visited this mark four times to try coaxing something out from underneath the paint, but have not been successful. In addition to these survivors, I classified another 78 marks as "Not Found," meaning that the mark might still exist, but is buried or covered. These include city monuments, some chiseled marks on doorsteps, and tablet bolt 505 which is on a church in Rockaway that still survives but is likely under a recent façade. The majority of Koop's marks, 131 in all, clearly have been destroyed by the winds of progress that have swept through Queens over the past century. If anyone else has been successful at finding any other Queens County marks established by Koop, besides the ones that I've listed, please let me know so that I can revisit them. I am going to try to find all of Koop's marks in the other boroughs, as well, and have made good progress because those counties' streets have mostly not changed, and because there are many more surviving marks. I will post my results as I finish each county.

I believe that the USGS became part of the NGS which is now part of NOAA, so USGS marks from the early 20th Century could/should be in the NGS database. Of course, the operative words are "could" and "should." You can also search in the Archived datasheets, though I doubt that you'd find it there. Remember, of course, that a recovery report that says "not found" is, like our geocaching entries, just a statement that someone couldn't find the mark. The mark could well have existed at the time of the report, but it could have been buried in dirt or sand, or was in a flooded area, or hidden copious amounts of poison ivy. A metal detector may be of use for your recovery efforts, too. One complication that I've found when searching for older marks is that, even with the datasheet, landmark references may have changed. A few examples are that a road was widened, so the mark is closer to the curb than before. A telephone pole was replaced so the distance to that new pole is now slightly different. A bridge was replaced, which could have destroyed the old mark, or part of the old bridge structure was incorporated into the new one and the mark is now at a different distance from other bridge reference points mentioned in the datasheet. As for submitting recoveries, NOAA will take them online: http://geodesy.noaa.gov/cgi-bin/recvy_entry_www.prl . I've heard through the grapevine that NOAA no longer cares much about intersection stations (landmarks) like water tanks, church steeples, radio towers, etc., but does still care very much about benchmark disks. NOAA is still active in this area (NY) and well over 5% of the benchmark disks that I have recovered have been set, or reset with a different PID, within the last 15 years, i.e. not in Groundspeak's database but in the current NGS database, with a trio of Tidal benchmarks set as recently as 2014 and not yet even in the NGS database. Happy benchmark hunting!

So, on these USGS topo maps, if it is an "X" only, with no "BM" or triangle, I should not expect to find any physical object set by a surveyor - is that correct? [/b] This was a general question but currently I am searching for the location of a U.S.G.S. mark set between 1910 and 1919 somewhere in the vicinity of the Yachats River Road on the map. The mark has since been destroyed but may or may not have been recorded as such. I believe the elevation of the mark was 44 feet but I am still trying to confirm that. It looks like the mark was NOT at 64 feet. Thanks You're welcome for the help. Yes, an X without the BM symbol should not produce a disk. As for the mark you're trying to find... assuming that it's in the NGS database, you can search for it, even without the name of the mark. This should help to narrow the focus of your search, and help you to corroborate the benchmarks shown on the map. Go to http://www.ngs.noaa.gov/cgi-bin/datasheet.prl and click on Datasheets, then enter a search. You might try, for example, entering a "Rectangular Search," which means that you'll search by ranges of longitude and latitude, or a "Radial Search" which means that you'll search for benchmarks that are within a certain distance of a specific longitude and latitude. You do not need to know the designation of the mark for either search, but the mark's designation will be part of the search results. The year that a mark was set is part of the results, so you'd be looking for something set between 1910 and 1919 and, from what you mentioned, marked as destroyed. The second-from-the-right column of the search results is the mark status: S = set and not yet revisited; X = destroyed; N = not found; O = other (bring up the datasheet to see specifics); G = good, P = poor. Unless you know for sure that the mark has been destroyed, don't necessarily rely completely on this status. A mark that's "good" might not have been revisited in decades and has been destroyed. A mark that's "not found" could still exist, and I've seen quite a few datasheets in which the NGS designated the mark as "not found," only to find the mark in a subsequent visit and mark it as "good." As for elevation... older disks were often stamped with their elevation as of when they were set. However, sea level has changed over the past 100 years, so your benchmark's actual elevation today, in the NGS database, is likely a foot or two lower than it was in 1910. Since you seem to know the approximate location of the mark better than you know its elevation, you might narrow your search by location first, and then decide which benchmarks might be yours based on a range of possible elevations, e.g. 40 to 70 feet. With luck, you won't have a very large number of benchmarks to consider. See where this leads you. Hope this helps.

As mentioned before, the letters "BM" mean benchmark, which means that a disk was set at the location of the X (vertical benchmark station), or at the location of the triangle (triangulation station). I've also seen instances where a triangle does not have the BM next to it, but there is a triangulation station set there. An X without the "BM" means that the elevation has been determined, but that there is no disk. Often these are at road intersections, for example, or at the top of a hill. In this case, if the X is printed in black, the elevation has been field checked. If the X is in brown, the elevation has not been field checked. My experience has been that topographic maps often do not contain a good number of disks. Some were just never printed on the map. Others are Tidal benchmarks, which seem to be rarely shown on maps. Still others may have been monumented after the last map revisions. Of course, many disks may have been destroyed since the last map revisions, too. And triangulation stations are generally a group of four marks - the station itself, plus two reference marks and one azimuth mark - but the triangle symbol only marks the location of the actual station. You need the NGS datasheet to find the other disks. Hope this helps.

Out of curiosity, would the "PNLS" be an abbreviation for Pinellas, which is Clearwater Beach's county? Is the marker in question a county survey mark, which might not be in the Federal database at all?

Wow, I didn't know its possible to search by description letter! How did you do that? Wonderful info, thank you so much! Bring up the NOAA datasheet retrieval page: http://www.ngs.noaa.gov/cgi-bin/datasheet.prl Click on the DATASHEETS button. You'll see about 10 different ways to retrieve datasheets. For this particular search, I selected STATION NAME. I've used many of the others over time, too. I then entered the station name, with a "*" wildcard, and I had to select a state, then I clicked SUBMIT. My search was for "E*" and I chose Colorado, which meant that I wanted all benchmarks whose name starts with E in the entire state of Colorado. I got a list of benchmarks and just scrolled down, first looking for E217 (Station Name is the rightmost column), then looking for other names that could have been possible transcription errors, and found E271 with the 1941 data. A similar search could have easily found F217, as well. On the results page, you can sort the list that you retrieved by any one of its 12 data columns, so I could have, for example, ordered the results by date monumented, or latitude, condition (very useful to filter out NOT FOUND marks), etc. Hope this helps.

I did a name search on the NGS datasheet retrieval site for all benchmarks in Colorado that start with "E". There's nothing for E217. However, there is an E271 which was monumented in 1941, which matches to your benchmark's date. Perhaps that's the correct name? E271's PID is JJ0517 if you want to check its particulars. Hope this helps.

Yes, I definitely do get excited when finding a benchmark for which there has not been an NGS report in decades. I have found quite a few 1932-era benchmarks for which I am the first to find on Geocaching and for which there have been no NGS logs since the mark was first set. And, I agree about the Tri-station effect. I guess these are feelings that only another benchmark hunter can understand LOL. I use the baseball term "four-bagger" to describe finding the four benchmarks in a Triangulation station. Around the NYC area, at least, such finds seem to be very rare. I think that I've found only about two: KU3087 (Tappan, in Glen Cove, Nassau County) and KU4067 (Nodine Hill in Yonkers, Westchester County) come to mind. KU4067 was especially nice because it was my 100th FTF benchmark. It's a disappointment to read a tri-station box score to find out that there was no azimuth mark set. Sometimes, NGS used an intersection station, for example, as the azimuth mark. But where four marks were set, it's always exciting to anticipate that I might find all four. But, too often, I end up finding only three, but spending an inordinate amount of time trying to find that elusive fourth mark, usually the azimuth mark because it's not part of the station/RM cluster, so is more likely to have not been spared from destruction.

In looking at the recent picture, I'd be very curious about what appears to be something atop the center of the dome. If it's the base of the flagpole, which it might well be, then I'd log it as Found, though probably in Poor condition because the flagpole itself is missing, much like a diskless stem for a benchmark disk.

The question, then, would be what are the stampings on B 197 and C 197? Are those, also, Esso disks, with additional stampings of B 197 and C 197 and the date 1991, or were those originally set by the MD Highway Admin? If the B and C disks are actual MD disks and were originally set in 1991, then the A disk may well have been an old Esso disk that was reused by the State crew. I'd also ask, too, whether the original Esso disk, if set by Esso, would have had ANY stampings like "A 197" which is a Federal or State marking. And are there other Esso disks in the area that are NOT stamped with a Federal or State designation?

Didn't mean to be misleading, just suggesting that we don't know the whole story and we are left to suppose. For example, is it possible that the mark was monumented, say, in 1970 (in the "Esso" era), and then in 1991 a Maryland SHA crew comes along, properly surveys and documents the mark, and stamps the pre-existing disk "1991" before reporting to NGS? I'm puzzled by that date.... -ArtMan- Artman, You may well be on to something about the re-use of disks, and I've seen a number of examples of this in my local area, though I don't think that any of the disks I've seen has been restamped. I'm curious about the digits "9" in the 1991 date. From what I see, the font in the date "9"s may not match to the "9" font that stamped the 197, although getting run over by a truck can alter appearances a bit. The 1991 date is also sloppy, whereas the A 197 stamp is straight across. Yes, I've seen sloppily done Federal marks, but this does lend credence to the theory that it was monumented during the Esso era, then restamped in 1991. Exxon, I believe, still sells fuels under the Esso name outside of the US. Within the US, Exxon did continue to sell Esso Diesel after the Esso-to-Exxon rebranding in the early 1970s, so that Exxon would not risk losing the Esso trademark by disuse.

No reason to eliminate destroyed marks, although their status could be updated from the NGS database. Adding new marks is very easy. The entire process would be... download the NGS datasheets and convert them into a database. A given PID is in one of only three statuses: it's in the current Groundspeak database, but no longer in the NGS database, in which case it's been archived by the NGS; it's in both databases, in which case it's still active, but may have been updated in the NGS database; it's in the new NGS database, but not in the current Groundspeak database, in which case it's a new benchmark. So (1) for every PID that's in the current Groundspeak database but not in the "new" NGS database, add a status to those Groundspeak records to indicate that it's been archived by the NGS (one might even be able to download archived datasheets from the NGS website and use that set as the driver for this step); (2) for every PID that's in both databases, but for which there are new History/Recovery records in the NGS database, update the Groundspeak database with new NGS data; (3) for every PID in the NGS database but not in the Groundspeak database, add those records. The time consuming aspect of this is downloading the NGS datasheets for 3100 counties, but downloading, say, even as few as 50 counties of data per day would take only about 2 months for all 3100 counties. Assuming that the Groundspeak database was set up to allow for updates, everything else is very easy database programming, and reusable once programmed for the first time. With a little more effort, Groundspeak's database, and its front-end queries, could be made so much more useful, too. For example, maybe it's winter, and I'm looking, specifically, for landmarks because I know that they're not going to be covered by snow, and I want those landmarks in a specific quad, or county, too. An easy query, but impossible, currently, in any automated fashion, with Groundspeak or the NGS. Or, maybe I'm a newbie and I'm looking for easy benchmarks, whether recovered in Groundspeak, or not, that have had an NGS "GOOD" report within the past 5 years, or that have had a Groundspeak "Found" reports within the past year. Or I want a challenge, and I'm looking for benchmarks that the NGS says are still there, but which Groundspeak members have been unable to find. All of this logic is very easy to program and, in my opinion, would add tremendously to the possibilities of this hobby. Here are two more good queries - once I find my benchmarks, optionally tell me the geocaches that are in proximity to my benchmarks - or, if I'm looking for caches, optionally tell me the benchmarks that are in proximity to my geocaches. Groundspeak could easy cross pollinate the two hobbies, and everyone - Groundspeak, its user community, the NGS, and our hobbies - would benefit.

To update the benchmark database, there really would not be a need for a CD. Every benchmark's datasheet is available on the NGS website. One could, for example, download all datasheets for a quad, or for a county within a state, etc. Datasheets are flat text files and are very rigidly structured, with keywords at fixed columns on every line of pertinent data, and it would be an easy programming exercise to extract the necessary data to populate a database with PID, state, quad, latitude, longitude, marker type, last report status, report details, etc., together with a link to the NGS database for the full datasheet, should someone want it. The latitude and longitude could easily be converted to any numerical format desired. There might even be free programs, possibly with source code, to do most of this because it's one method of creating a GPS POI file. The time-consuming aspect of this would be to manually download the datasheets for all 3100+ US counties, but it could be done over a period of time.

Hi, I sent you a note earlier this week. Hopefully we can connect! Thanks, Erica I most certainly stand corrected and apologize for my disbelief. However, as a jaded New Yorker who saw the original posting dated April Fool's Day, my conclusion was not entirely unreasonable . Would love to see the story when it comes out.

I'm a skeptic of the post, too, given the date. Would the Wall Street Journal really have a reporter assigned to cover a non-business topic like benchmark hunting, and be willing to send that reporter to anywhere in the US to watch someone find a benchmark? Nevertheless, I checked out benchmarks at the intersection in question, and it's interesting that there is no NGS database benchmark at that intersection and, apparently, benchmarks along Santa Monica Blvd. in that area are, generally, on the curb, not in the middle of the intersection. The closest benchmark is R773, located about 1 block southwest of the intersection, but listed as Not Found in its 1965 recovery report. The next closest is mark S773, located a few blocks northeast of the intersection. Also - Santa Monica Blvd. in that area is North Santa Monica Blvd., and Palm Drive is North Palm Drive. I'd assume that one wouldn't drop the "North" from a street name, especially twice, and especially from North Palm Drive, which seems not to exist without a North or South designation. LOL!

Is the 50-100' number some kind of standard? I'm not sure I've ever found scaled coordinates to be within 100'. My expectation is within a tenth of a mile, but I keep my mind open to a even larger offset. Maybe that's just California. Not necessarily a standard, just an observation. Scaled marks' coordinates are produced from someone reading a map. If the mark is accurate to 1 second of longitude or latitude, those are roughly 100 feet. Maybe I've been influenced by benchmarks in New York City, many of which are set on buildings, which may make scaling more accurate. And, truth told, I have searched for, and found, marks further away than 100 feet from the datasheet's coordinates.

I will search for a marker until I'm satisfied that I'm not going to find it. A rule of thumb is that I'll probably call off a search after 15 minutes, or so, though I've searched for longer, at times, and, sometimes, I'll look for another nearby benchmark that I can use as a reference point for my GPS. Remember, too, that "scaled" benchmark locations are only accurate to about 50 or 100 feet in each direction, which means that you could be searching for a 4-inch disk within an area of 1/4 acre. A keen eye is invaluable, and experience becomes key. Even when there are photos from a previous benchmark hunter, those could be, for instance, almost 10 years old, and lots could have happened in a decade: construction, painting/repainting of the benchmark, natural disasters, etc. I do my homework before looking for markers, so I have some idea of whether there have been significant changes to the locale, or whether there are possible typos in the datasheet. I try to go after benchmarks that I believe I have a chance to find, i.e. not marks that were on buildings demolished decades ago. I plan my route, but also allow for changes as I go along. And I've learned, in New York City, to take the time to look for other survey marks near any benchmark that I've found. Benchmark hunting does produce "statistics," but the real fun, for me, has been learning about New York City's history and geography, as well as getting outdoors and enjoying the fresh air. It's also exciting to find a benchmark that hasn't been logged for decades.

Benchmark hunters in New York City are probably aware that the New York City Board of Estimate and Apportionment, basically the political body that ran New York City from 1898 until the US Supreme Court declared it unconstitutional in 1989, commissioned a survey of the entire City in 1909. The survey was headed by Frederick W. Koop, and it covered all five boroughs of New York City, took five years to complete, and resulted in the establishment of 1186 survey marks throughout the City. Upon completing the survey, Koop published a monograph, "Precise Leveling in New York City," which details the precise location of each survey mark. Copies of the original manuscript are available in some local NYC libraries, but the University of Michigan, apparently the recipient of an original copy in 1916, has published this work in softcover, and I want to let the benchmark hunting community know that this work is available on Amazon.com for a very reasonable price. It is an invaluable guide to the copper bolts, chiseled squares and crosses, and other surviving marks from that epochal survey of New York City. Only a few of the survey's 1186 marks have been included in the USGS database and have datasheets. Those that have been included in the USGS database usually either have numerical designations from 1 to 1186, or may have "NYBE+A" included in their designation. However, some have become known by the landmark to which the marker was affixed, e.g. "PS 34" in the USGS database is on Public School 34 in Queens, but happens to be Koop Survey mark 590. One footnote to this survey, however, is that all locations are reckoned, of course, to street names as they were in 1909. Queens County, in particular, underwent an almost complete renaming of its streets in the 1920s, subsequent to the 1909 survey. Fortunately, there is a website with tables of old and current street names, which has, also, proven itself extremely valuable for attempting to find these survey marks. Here is the website link: http://stevemorse.org/census/changes/QueensChanges1a.htm. A similar problem arises, less often, with changes in the numbering of Public Schools, but the street location should be sufficient to find a survey mark, if the 1909 school building survives. Happy Benchmark Hunting!!