Mike, you wrote:

> but your primary quest point mxn just happens to be the essentially
> exact position of the confluence in 1849
> the year of the first mxus survey
> which began expressly & precisely at the middle of the gila colorado
> confluence as determined by &or at the time of this survey anyway
>
> so your first quest point is also your very best bet for your second
> quest point
> hahahahaha
>
> talk about finding 2 needles in the same desert or something

I'm afraid that I must differ with your assessment that the location of the
historic tripoint of Mexico, California, and the New Mexico Territory (between
the Mexican Cession of 1848 and the Gadsden Purchase of 1853) was substantially
the same as the current AZCAMX.

I think that this misconception arises from the specification of the confluence
of the Gila and Colorado Rivers as the eastern terminus of the geodesic segment
of the MXUS boundary. Since this segment now terminates at the Colorado river,
it is very easy to overlook that it formerly extended at least six miles farther
eastward, until the Gadsden Purchase rendered that part of it moot.

The proof is at http://tinyurl.com/yp69 , where you will see that the ghost line
survives in the cadastral land survey, which is reflected in part by the
location of a highway and a canal.

The geodesic segment originally terminated at the confluence of the rivers,
which was then somewhere in the bottoms northeast of what is now downtown Yuma.

Lowell G. McManus
Leesville, Louisiana, USA