I have found the description below of the fixing of the initial point of the
geodesic by the boundary commissioners in the 1849 survey. This is excerpted
from a joint report by the Committee on Counties and County Boundaries of the
Council (upper house) and the Committee on Federal Relations of the House of
Representatives of the Legislature of the Arizona Territory, meeting at Tucson
in December 1868:
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To those who are not conversant with the minute points of the geography of the
junction of these two rivers, it is necessary to say that at the junction, and
for miles around and above this junction, it is one immense mud flat, over which
the Colorado river (at all times when high) overflows; and all the apparent
circumstances go to show, and those who were on the ground at the time of
running the line by the Commissioners who fixed the line between the Republic of
Mexico and the United States, by the treaty of Guadalupe Hidalgo, say that all
of said flat country was inundated at that time.
This accounts for fixing the initial point up the Rio Gila some hundreds of
yards from its actual mouth, when both rivers are low, advantage being taken of
the high condition of the Colorado, in connection with the language of the
treaty, which says:
''That the boundary line between Upper and Lower California shall consist of a
straight line drawn from the middle of the Rio Gila, where the Colorado, etc.''
The high condition of the Colorado at the time, owing to the flatness of the
country, left the place of unity between the two streams very indefinite; but a
point was agreed upon between the Commissioners from which to start, for the
purpose of dividing the two Californias. But there is no good reason to doubt
but that the intention of the plenipotentiaries was at the time of making the
treaty, to cross the Colorado river directly from the fact that the general
course of the Colorado is north and south, and this dividing line runs directly
west; but owing to a short bend from south to west, this line starting from the
agreed initial point, did not cross the Colorado until the Commissioners had run
six and a half miles, cutting off a strip of land between the line and the river
on the west varying from a few hundred yards to three-quarters of a mile in
width.
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This report in the 1868 Arizona Territory legislature was occasioned by some
recent suggestions by California politicians that the last-mentioned strip north
of the geodesic and on the left bank of the Colorado might belong to them. This
is part of a long response that the joint committees made and sent to the
California Legislature to expose the fallacy in the California argument. The
whole thing can be read at
http://southwest.library.arizona.edu/hav5/body.1_div.2.html .
Scroll down to near the bottom of "[page 50]" near the middle of the long web
page. It extends from there to the top of "[page 57]."
At the end of the report, the following statement is inserted:
"The foregoing seems to have been conclusive as to that controversy as there was
no subsequent action taken in reference thereto by California or by Congress. "
Lowell G. McManus
Leesville, Louisiana, USA