--- "Lowell G. McManus" <mcmanus71496@...> wrote:

> confused by your three natches in
> a row.

no matter
just a timely frivol in message 18517
seeing as messages 18515 & 18516 both began with natch

> I should be able to correlate Ellicott's strip maps
> of the line with the USGS
> topo maps. His maps show stream crossings and the
> numbered mounds at one-mile
> intervals.

ok but be aware that ellicotts measurements
& 18th century measurements in general
do not exactly equal modern measurements

the discrepancy becomes clearest if you compare the
number of his mounds with the actual mileage today
there between the mississippi & the chattahoochee

it is something on the order of 10 percent off
i seem to recall

tho i much appreciated the following analysis

& will insert my secondary opinion at the best point

> The mile mounds number eastward from an initial
> point that Ellicott called
> "point D," which he described as "at the foot of a
> steep hill." There is every
> indication from his maps that this hill is the bluff
> that constitutes the
> geomorphologic valley wall at the edge of the
> Mississippi River flood plain,
> just west of the intersecting valley of Hunter
> Creek. In the numbering scheme,
> point D would equal mound number zero. (Points A,
> B, and C had to do with his
> calculation of the precise 31st parallel by
> astronomical and geometric means,
> but are not necessarily on the line itself.) From
> point D, Ellicott started the
> line eastward up into the loessial Tunica Hills,
> then corrected its deviation to
> within the limits of his instruments. Next, he
> surveyed back westward through
> point D to the bank of the river. Here are his
> words:
>
> "The line being extended to the margin of the
> Mississippi on the 17th of August,
> the measurement from the point D was found to be 2
> miles and 180 perches English
> measure, or 2111.42 French toises. At the distance
> of 1 and 2 miles at the
> points x and y, were erected square posts surrounded
> by mounds of earth, and at
> the distance of 88 French feet from the margin of
> the river, and in the parallel
> of latitude was erected a square post 10 feet high
> surrounded by a mound of
> eight feet in height. On this post is inscribed on
> the south side a crown with
> the letter R underneath; on the north U. S. and the
> west fronting the river,
> Agosto 18th, 1798. Lat. 31° N."
>
> I find that an English perch is equal to 16.5 feet,
> precisely what we would call
> a rod. A French toise is six French feet. A French
> foot equals 1.06575 English
> feet.
>
> Thus, the tall mound near the river (which
> Ellicott's map calls "point z")
> should have been 13,436 feet (approximately 2.54
> miles) west of point D at the
> base of the bluff. The bank of the river is now
> approximately 3.8 miles west of
> the bluff. Therefore, the tall point z mound might
> possibly survive--if the
> river didn't meander eastward before meandering
> westward.

yes indeed
& the whole flood plain is a big if
as you must also realize

not to mention again the unreliability of the
measurements

& the disagreeableness of the general locality

but i would agree it looks like the mound at point d
will be the oldest
in case that somewhat matters to you too

but in view of the great overall difficulty
nay enormity
of your quest
i would just go for the most agreeable & easiest
looking one
or few
from whatever other map synergy you can find

what a delicious task tho

if you can conveniently share any more data or maps
please by all means

> I have carefully measured eastward from point D on
> my maps and the topo maps at
> TerraServer. I have determined that the benchmark
> on the LAMS boundary just
> west of US 61 is not at a mile interval.

ok but again i think all these measurements will
already have gone poof if youve done the math
suggested above

which is still not to say here nor there
but just to possibly refresh the questions

> other
> elevations on the topos
> that I have found along the western part of the line
> are stated elevations, not
> bench marks.

are you concluding & or precluding something here

or do you still imagine all 17 or so specially
indicated points on the lams line remain equally
plausible mound guesses

btw
the only ones i am shrugging so far are the public
land survey corners
since they seem so obviously derivative of the mound
line itself
i mean
rather than being at all necessarily based on the
individual mounds

> I have also selected a
> few likely hypothetical mound locations that should
> be relatively accessible.

yes these choices will be most interesting
if you care to enlarge on them

> I am now pursuing a wild theory that will require
> some research for confirmation
> before I enunciate it. I'll let you know if it pans
> out. I want to get that
> straight before planning any travel.

hahaha
well i will want to check any maths & logics too
but by all means let us know what you are thinking

> I might also
> want to wait until the leaves
> are off and the bugs are fewer.

definitely
even if just to prolong the pleasure

am doing the same with hapiri here
which is put off again til at least monday btw
due to high water
but who cares why

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