Us Department Of Interior Benchmark

[+kc8hnz]

Today I found a benchmark set by the US Department of Interior. It wasn't listed, but it is on a USGS topo map for my area. My question: What do they do in regard to surveying, and why would it not be listed? I know a lot of the USGS disks arn't listed simply because they never made the effort go through the old paper files and regester them with the NGS, whould this be a similar reason? Also, has anyone found one that was listed?

 

N 41 14.236 W 82 1.387 Beldon, Ohio set on a railroad

bridge crossing SR 303

[+GEO*Trailblazer 1]

BLM(Department of the Interior) is resposible for the PLSS Public Lands Survey System.

[ckhd]

I know where four dept of int disks are. They are on the four corners of my dad's property, but they aren't listed on the Internet.

 

My guess, the Forest Service just doesn't list them all.

[+rogbarn]

What you have found is a USGS marker. Note the "Geological Survey" on the disk. The USGS is part of the Dept. of Interior. It also explains why it shows up on the topo map which (obviously) is also done by the USGS. The Forest Service is part of the U.S. Dept of Agriculture. Their disks also show both the department name and the agency name (at least the ones I've seen). See HB1859 and HB1861. HB1861 is a good closeup of the disk.

[Z15]

Forest Service - USDA (US dept of Agriculture)

Geological Survey, USGS etc - Dept of the Interior

C&GS, NOS, NGS - Dept of Commerce

 

Probably better than 50% of all USGS marks out there are not in any database, let along the NGS db which the info on this site comes from. USGS marks were set in support of USGS mapping efforts. Many of these marks only exist in paper form and the amount of time and effort to digitize them would be cost prohibitive. Many of the marks lack very good descriptions and/or were surveyed using questionable methods. Mapping did not require a lot of precision. USGS may even consider them obsolete by todays standards.

 

When you find a USGS mark in the NGS database, 99 out of 100 its because a C&GS or NGS survey crew found the marl and used it in their survey. USGS had other responsibilities and organizing survey control in a database was not one of them. You can get information in manuscript from from USGS if you supply them with a USGS map name and state. They will charge a few for this info.

 

DaveD responded to this same question a while back and offered a vg explanation.

Edited February 10, 2004 by elcamino

[+wildearth2001]

I have a lot of those near here

[+chaosmanor]

Another thing to make a mention of is that many times, the little BM note on topo maps will refer to local marks set by other than the USGS/CGS/NGS. I've run across several of these in California. It can be quite a challenge to find a marker using just a "+" on a map! While many of the markers in the official listing are local marks, nowhere near all of them are in the NGS database, nor could they have use for all of them, I would imagine.

 

Recently, I did some BM searching along California State Route 126, between Santa Clarita and Ventura. I couldn't find a single one of the marks that I was looking for - the highway was widened a few years back, and I think many of the makers were buried or removed - but I did find a lot of old Cal-DOT Bathey Cap T-bar right-of-way markers. The first two or three were right near where BM Descriptions were having me look for CGS disks, and I thought that the Monumenting Reports must have been done by drunken trolls or something; about drove me nuts until I finally realized what they were!

 

Speaking of CalTrans, they did some recent (past 2-3 years) center-divider work along many miles of US 101, and planted a bunch of new survey markers in it. A few are replacements for older markers that were reported to the NGS long ago, but most of them look to be quite new. I haven't seen any new datasheets for them, but I'd love to know if any of them were even reported, or if NOAA is taking new marks that aren't NGS-monumented.