I photographed these two beauties in northern Nebraska on my way out to the Black Hills. Both were placed in 1901 and are great examples of the "Limestone Post" bench mark that USC&GS used during the pre-brass disk era.
http://www.penryfamily.com/surveying/uscgsa3.html
http://www.penryfamily.com/surveying/uscgsd3.html
How long are those posts when standing on the surface? Just curious. I love your photoblogs about your finds.
Jerry, I have no experience with this type of benchmark monument. Is it intended that the rod be held inside the small square cut-out?
That was my question also. Some do not looked plumbed up all that well now.
A 3 is NGS data sheet no0006
D 3 is NGS data sheet no0033
I see you reported recoveries in 1997. It might be worthwhile submitting another report giving better coordinates (handheld GPS or better) to help locate them and saying they are still there.
The limestone posts are approximately 24"-30" long. Yes, it was intended for the USC&GS leveling rod to sit down in the square cut hole. The problem is that the hole is 1 1/4" square and will not facilitate a modern Philly rod. I have see where someone chiseled out the hole on one to make it bigger instead of just adding the differece to the bottom of the hole to their rod shot. I plan to update the datasheet on these and have GPS positions. The "scaled" positions on the datasheets are often several hundred feet off.
