I thought should post a picture of something survey related just so no one thinks I was among those banned. Some shots were fired across the border earlier last week, so I luckily pulled back before the real shooting got started.
These 5 3/4" diameter cast iron caps were set in the late 1880's and early 1890's in Missouri, Iowa, Nebraska, South Dakota, North Dakota, and Montana. Enjoy!
I have revovered a few of them. http://www.penryfamily.com/surveying/morcmain.html
Interesting in that they appear the same as Mississippi River Commission caps. With both being referred to as "MRC," it never occurred to me that you need to know where you are to discern which is which from just the abbreviation.
Must/might make things a bit confusing around northern St. Louis, MO.
The ones along the Lower Mississippi were commonly set above underground marks that were enclosed in clay pots. I've seen lots of re-surveys by the Corps that published the elevations of both the underground marks and the re-set surface caps.