an observation on pre-1900 BM's

[topflitejr1]

I have noticed that most pre-1900 BM's along the coast of California were Monumented by burying 1 or more glass bottles 6" to 3 ft underground. Question #1 is, How were these Stations used? Many of these "BM's" were later recovered and a Disk was placed directly above the bottle(s) and the original Monumented date was stamped on the Disk. So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

[Papa-Bear-NYC]

I have noticed that most pre-1900 BM's along the coast of California were Monumented by burying 1 or more glass bottles 6" to 3 ft underground. Question #1 is, How were these Stations used? Many of these "BM's" were later recovered and a Disk was placed directly above the bottle(s) and the original Monumented date was stamped on the Disk. So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

There's really two questions here:

 

1) How were they supposed to use these markers? The markers in question were triangulation stations (true bench marks were never buried) and they were buried (so I have read) to discourage locals from digging them out and taking them home. They were used by subsequent parties which followed careful directions and diagrams and dug and dug until they found the station. If they couldn't find it - it was lost. Later on they would put an underground AND a surface mark and dig up the underground mark ONLY if the surface mark was missing. Nowadays with GPS stations, they set ONLY a surface mark. Such is evolution.

 

2) The question of dates and RESETS is inconsistent and confusing. I think most would agree now that when a monument is replaced, even in the same spot (such as mounting a disk in a drill hole in a rock) the designation should add the word RESET. But either the rules were less well spelled out in pre-1900 or they were not carefully followed.

 

The worst example I've found is this one: KU3532 Prospect Water Tower 1903

First - the tower was torn down in 1930 and local surveyors had preserved the position and placed a monument where the original tower stood.

Second - in 1937 the land was relandscaped and the monument was reset 8 feet lower.

So this one should be called " Prospect Water Tower 1903 RESET RESET" Go figure!

 

Be happy when you find one of these stations. Be even more happy if you find one with the original monument The ones still left would tend to be copper plugs - I'm sure no one is likely to find a 150 year old bottle a foot underground!

Edited February 2, 2008 by Papa-Bear-NYC

[topflitejr1]

I have noticed that most pre-1900 BM's along the coast of California were Monumented by burying 1 or more glass bottles 6" to 3 ft underground. Question #1 is, How were these Stations used? Many of these "BM's" were later recovered and a Disk was placed directly above the bottle(s) and the original Monumented date was stamped on the Disk. So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

There's really two questions here:

 

1) How were they supposed to use these markers? The markers in question were triangulation stations and they were buried (so I have read) to discourage locals from digging them out and taking them home. They were used by subsequent parties which followed careful directions and diagrams and dug and dug until they found the station. If they couldn't find it - it was lost. Later on they would put an underground AND a surface mark and dig up the underground mark ONLY if the surface mark was missing. Nowadays with GPS stations, they set ONLY a surface mark. Such is evolution.

 

2) The question of dates and RESETS is inconsistent and confusing. I think most would agree now that when a monument is replaced, even in the sem spot (such as mounting a disk in a hole in a rock) the designation should add the word RESET. But either the rules were less well spelled out in pre-1900 or they were not carefully followed. The worst example I've found is this one: KU3532 Prospect Water Tower 1903

First - the tower was torn down in 1930 and local surveyors had preserved the position and placed a monument where the original tower stood.

Second - in 1937 the land was relandscaped and the monument was reset 8 feet lower.

So this one should be called " Prospect Water Tower 1903 RESET RESET"

Go figure!

 

Be happy when you find one of these stations. Be even more happy if you find one with the original monument The ones still left would tend to be copper plugs - I'm sure no one is likely to fins a 150 year old bottle a foot underground!

 

Thanks Papa Bear, It made sense to bury the "marks" back then so that they wouldn't be disturbed, but what a hassle it must have been for them to have to hunt them down and dig them up to use them. Someone eventually got the bright idea to set the Marks more permanently on the surface ( good thing for us BM Hunters!) In the mean time, I will probably log these older ones as found on GEOCAC, as I find there Disks (with a caveat). I would guess that to officially report these to NGS, one would have to physically find the underground Marks.

[2oldfarts (the rockhounders)]

So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

 

The simple answer is yes, if the description says it is a disk. If there is no mention of the disk in the description, then you did not find the station.

 

Does the description say that the bottle was removed? Does it say the disk was set above the bottle? If not then the bottle may still be there.

 

Like some Triangulation stations with underground marks, it all depends on what the description says as to whether it is a reset or not. If the underground mark is intact, but the surface mark is reset, is the station a reset? Technically no since the underground mark is the actual station.

 

I'm referring to the official description on the benchmark page when i say description.

[+Klemmer]

From my experience, it can go various ways. Examples:

1) You may find the original, like this drill hole from 1899, never found before: FS1138

Klemmer tips his hat to the 2oldfarts, partners on that one. Two others similar ones are nearby.

or

2) A disk has replaced the original marker, the date is retained in the records, but not on the disk, like TZ1974

from 1862.

or

3) A disk has replaced the original marker, the date is retained on the disk (check the picture & datasheet), but sometimes the records are a little messed up, like TZ2013. I think the datasheet should be monumented in 1860, but that's just me!

 

Regardless of how it shakes out, the really old ones sure are fun!

[topflitejr1]

So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

 

The simple answer is yes, if the description says it is a disk. If there is no mention of the disk in the description, then you did not find the station.

 

Does the description say that the bottle was removed? Does it say the disk was set above the bottle? If not then the bottle may still be there.

 

Like some Triangulation stations with underground marks, it all depends on what the description says as to whether it is a reset or not. If the underground mark is intact, but the surface mark is reset, is the station a reset? Technically no since the underground mark is the actual station.

 

I'm referring to the official description on the benchmark page when i say description.

The Rockhounders come through again! Thanks for the reply. But to clarify your answer to my second question; If I were to find a Station monumented in 1887 with a glass bottle buried 20" underground and the Station was recovered in 1933 with the bottle remaining in place, but a disk stamped 1887 ( with no RESET) placed directly above the bottle at the surface *as he catches his breath, hoping no English teachers are reading his loooong sentence*, I can log the station as found as long as all the above is mentioned in the details. Correct? Thanks for your patience on this one.

[2oldfarts (the rockhounders)]

So, my second question is: If I recover a Disk with the original Monumented date stamped on it (with no RESET stamping), can I log it as Found using the original Monumented date?

 

The simple answer is yes, if the description says it is a disk. If there is no mention of the disk in the description, then you did not find the station.

 

Does the description say that the bottle was removed? Does it say the disk was set above the bottle? If not then the bottle may still be there.

 

Like some Triangulation stations with underground marks, it all depends on what the description says as to whether it is a reset or not. If the underground mark is intact, but the surface mark is reset, is the station a reset? Technically no since the underground mark is the actual station.

 

I'm referring to the official description on the benchmark page when i say description.

The Rockhounders come through again! Thanks for the reply. But to clarify your answer to my second question; If I were to find a Station monumented in 1887 with a glass bottle buried 20" underground and the Station was recovered in 1933 with the bottle remaining in place, but a disk stamped 1887 ( with no RESET) placed directly above the bottle at the surface *as he catches his breath, hoping no English teachers are reading his loooong sentence*, I can log the station as found as long as all the above is mentioned in the details. Correct? Thanks for your patience on this one.

 

Yes, that is correct. If the bottle is still underground and the disk was placed over the bottle and it is so documented in the description, then you have a valid find. You surely wouldn't want to try and move the disk, just to verify that the bottle is still there, so we take their word for it (that it is still there) in the description.

 

We have to agree with Klemmer, finding the old ones is one of the most satisfying aspects of benchmark hunting. If you recover one of those bottle/benchmarks be sure to take plenty of pictures and post them here in the forum and gloat as much as you'd like about finding it!

 

John

[topflitejr1]

From my experience, it can go various ways. Examples:

1) You may find the original, like this drill hole from 1899, never found before: FS1138

Klemmer tips his hat to the 2oldfarts, partners on that one. Two others similar ones are nearby.

or

2) A disk has replaced the original marker, the date is retained in the records, but not on the disk, like TZ1974

from 1862.

or

3) A disk has replaced the original marker, the date is retained on the disk (check the picture & datasheet), but sometimes the records are a little messed up, like TZ2013. I think the datasheet should be monumented in 1860, but that's just me!

 

Regardless of how it shakes out, the really old ones sure are fun!

 

Wow! a response from the Legendary Klemmer & Teddy Bear Mamma and The Rockhounders both in the same day! (I'm not worthy!!) Thank you very much. I clearly have a much better understanding now on advanced Benchmarking or would Post-graduate Benchmarking be a better term? Yes, the older BM's can be much more challenging and can require more investigative work to find and decypher. You and the Rockhounders are awesome. Thanks again, and by the way, next time you pass through Page, give a little wave just West of the airport to my sister and her family (AZ Condors) as they are aspiring Geocachers/Benchmark hunters in need of a little Inspiration. P.S. notice that I didn't ask how you got onto San Clemente Island *wink*

[+Klemmer]

Legendary?????!!!!!

[topflitejr1]

Legendary?????!!!!!

 

Yup! Legendary: well known; famous or renowned.

[2oldfarts (the rockhounders)]

Legendary?????!!!!!

 

Yup! Legendary: well known; famous or renowned.

 

Don't know about you Klemmer, but I think he means we (the rockhounders) are infamous!

 

John

[2oldfarts (the rockhounders)]

Thanks again, and by the way, next time you pass through Page, give a little wave just West of the airport to my sister and her family (AZ Condors) as they are aspiring Geocachers/Benchmark hunters in need of a little Inspiration.

 

topflitejr1,

 

Just tell AZCondors to PM or Email us and we will help out in any way we can. Not to many cachers/benchmark hunters in this area.

 

Their one cache that they found (and you also) sounds intriguing. GPSr Accuracy Check Station cache link. We have always known that GPSrs are very accurate and this one lets people know just how their unit stands with the rest. Maybe that type could be their first cache to hide in the Page area?

 

We could also point the direction to go to get some awesome benchmarks.

 

Shirley~

[NGS Surveyor]

Pasted below is an article written by Joe Dracup (USC&GS geodesist) some years ago about marks used by the U.S. Coast & Geodetic Survey. I added the text within the [] and am working on a paper encompassing old style marks and USC&GS disks, with many photos. Some day...

GeorgeL

NGS

------------

HISTORY ARTICLE

 

SURVEY MARKS OF THE USC&GS and NGS

 

The following paragraphs are from "GEODETIC SURVEYS IN THE UNITED STATES - THE BEGINNING AND THE NEXT ONE HUNDRED YEARS, 1807 - 1940" written by Joseph F. Dracup. Comments within [] were added by the editor and photographs were added.

 

Station Monuments

Lasting station monuments, for obvious reasons, were always of fundamental importance in geodetic surveys. Where rock ledges or large boulders were available, Hassler utilized drill holes filled with sulphur or some other substance to reduce the effects of freezing.

 

Elsewhere, buried truncated earthenware cones were the rule. The center of the smaller radius end marking the exact station. Sub-surface (underground) marks also were usually set in the same fashion. In most cases, at least one reference (witness) mark was established, drill holes and cross cuts in rock structures and truncated earthenware cones, smaller than the station marks were standard. Hassler buried the reference cones in a specific pattern, providing visible reference information to locate the general station site, and in addition buried small pieces of rubble, sea shells and the like found at the site, atop the station mark to aid in the recovery.

 

Reference marks serve several purposes: To aid in locating the station, to verify its position, to reset the monument and for use as substitute stations.

 

Versatile Concrete

Base line stations were usually marked by heavy stone posts until about 1900 when poured concrete monuments replaced them. From about 1850 to the turn of the century, stone posts (marble, sandstone and limestone) 2-3 ft. in length, and for sub-surface marks the same type of posts, bottles, earthenware jugs and crocks and similar, generally replaced cones for marking stations. However, in some instances, bolts and nails cemented in drill holes, simple drill holes, cross cuts and in fact, almost any conceivable mark, in any combination with these station markings were utilized. When necessary to bury the marks, a ditch 4-8 ft. in diameter and 8-18 in. deep, surrounding the station location was usually dug and filled with coal or charcoal. Once concrete became readily available, 2-3 ft. long tile and tin pipes filled with the substance, set over underground marks were often employed with centers marked by bolts, nails, punch holes, etc.

About 1900, cast bronze disks were introduced and shortly thereafter poured concrete monuments 3-5 ft. deep with sub-surface marks became the standard, where rock ledges and boulders were not available. Monuments of this type continued to be used until the mid 1980's.

 

About 1965, steel rods driven to refusal with disks attached later were set for many surveys and in fact, are the basis for what are believed to be the most stable marks by today's standards.

 

In the 1920's, two reference marks were specified for each station and beginning in 1927, a third reference mark was set about 3 mile distant for use in providing azimuth control for local surveys and for determining magnetic declination. Standard azimuth mark disks replaced azimuth reference marks about 1935. [in the 1970's reference marks were set within 30 meters (one tape length) of the station. Reference marks were numbered clockwise from north and set about 90 degrees apart. Azimuth marks were set between 1/4 and two miles distant. For a time, azimuth marks were positioned and underground marks were set under azimuth marks.]

 

Bench mark monuments were of similar design until the late 1970's when special steel rod type marks were introduced. In the 1930's, precast concrete posts with bench mark disks attached were used for several years.

 

Prior to the late 1970's, all concrete monuments and disks were constructed of non-magnetic materials. Once GPS became operational, sub-surface, reference and azimuth marks were seldom set and [stainless steel] rod type station marks predominate.

[Bill93]

The article posted by George reminds me of a question I've had for some time. It is easy to see that the rod driven to refusal is a superb elevation bench mark. But is its horizontal position stable enough for high order accuracy? If you lift the lid on one of those and polish the disk (if it has one) you could move it by millimeters. I've seen some with roots pushing on them and those are definitely out of horizontal position by measurable amounts. If the rod isn't concentric with the cover, it is hard to tell which has been moved. What is the official horizontal accuracy limit for a driven rod?

Edited February 5, 2008 by Bill93