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City directrix?


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Walking the dog in Forest Park, St. Louis, this morning, I stumbled on this stone monument* at the edge of an athletic field.


It commemorates the site of a weather station, which was later relocated to the airport.The elevation is given as 80.073 feet above "city directrix."


That reference to "city directrix" puzzled me. I never heard the term, and the definitions of "directrix" in my unabridged dictionary weren't any help.


In St Louis, it turns out, the city directrix was a stone monument from which elevations (and possibly distances) were measured. Here's a description:


That's from a publication titled Descriptions and Elevations of Bench Marks on the Missouri River. (U.S. Engineers Office, Kansas City, 1912). Apparently, it's long gone.


Anyone else familiar with this term?





* Photo by Wordpress blogger Regenaxe

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... and a pdf copy of the book for your perusal:

Descriptions and Elevations of Benchmarks on the Missouri River


~ Mitch ~

This is the upstream (fourth from last - P 111) PID in that string.



QX0230 CallawayMT photo & equipment.


And third from last is a NONPID. NOTE - only 27 of the 307 BM's in Montana have PID's.

Many of the NONPID's have an X on the USGS Quads and can be found.




QX0420 Ditto on photo.


The cap and standpipe for B. M. 1 cannot be seen from the public streets in Three Forks (Old Town). I have not attempted to get to B.M., N. P. R.R. kayakbird

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I waymarked this monument a little while back. Your source book on the directrix is good, and is a bit more specific than what I had found. A neat book for the history of this marker is "Forest Park" by Caroline Loughlin and Catherine Anderson, 1986. It is partially online (snippets) but can be found in the stacks at Buder library near Forest Park. A photo of the police substation building the marker was originally next to is here. The meteorological station was in the tower of that building. The building was torn down around 1960.

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