The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1893-10-30
THE PRAIRIE MOUNDS.
A Theory of the Origin of the
Tumuli Near Olympia
TRACED TO GLACIAL PERIOD.


WASHINGTON srATE BrTLpTss. wosIp's
fAfR oEousrs. CHICAGO, Oct i2.-ISpecaal
correspondence. IA very interesting Wis
TOR has paid his respects 10 the Washing
tonians here during the past few days. II
- III. IT, y. Rogers. formerly Of Dorehes-
Ter. MASS, but recently removed 10 Hills
ooro, Or DR.. Rogers is one of those men
VINO DO not desire great riches. From his
profession he has acquired sufficient
money 70 keep him in comfort all the re-
fnainder OF his life, and he Is now devoi-
ing All his time to the pursuit OF scientific
knowiedge and research in the interesting
heids OF natural history. This study and
research has developed many facts new
and interesting. including q new and we'll
defined theory as TO the causes Of ocean
tides; but probably one Of the most inter
esting studies he has made, that 10, most
interesting to Washingtonsans. is the work
ne has performed in the Evergreen state
Many people have been greatly puzzled
and deeply impressed by the peculiar
mounds seen on the prairies between
olympia and Tenino. Probably there are
as many theories IS 70 the origin of these
mouads Is there are scientific men who
have seen them. but il has remained for
Dr. Rogers TO make the first close and
serutinizing examination of the mounds
and TO give the results Of this study to the
world The doctors monograph on the
Drift Mounds Near Olympia" which ap-
peared in q recent number Of the America n
Geolooia, an excellent scientific journal
published at Minneapolis, is so complete
and would prove of so much interest to the
readers of the PosT-IxTELLIGENcER, that
have secured a copy and would recon-
mend all my scientific friends to procure
ii, as IL will not be long before other inyes-
LEGATIONS viii be made in this and other
lines OF scientific research IN the compar-
atively unknown fields of Washington.
DIR. Rogers study is as follows:
DRIFT MOUNDS NEAR OLYMPIA.
Natures architecture is AWAY interest
ing. often beautifully but frequently the
history OF structure presents raany per-
picking difficulties TO solve. Toward the
western coast of Washington, a few miles
south of Olympia, are found an immense
number of peculiar tumuii. from three to
i've feet high. thirty feet, more or less, in
diameter, regular in size. having the form
OF broad-based cone, composed of a
heterogeneous mass of sand and gravel,
inclosing plentiful water-worn pebbles and
cobbles. such as usually appear in modi-
fed glacial drift. These mounds cover q
large area, embracing hundreds of acres,
for the most part open prairie with very
slight westerly dip. The forests, however,
have encroached to such an extent that
large numbers Of the mounds are found
within the timber. They can be numbered
by thousands, and are 80 plentifully dis
tributed that in the open prairie they
present the appearance of n vast field of
haycocks. They are without order. The
n - L.. L. IL
others are many yards apart. The nearly
level earth between the tumuli is more or
less strcwn with pebbles and cobblestones
similar in character to those of the
mounds. These heaps at once attract the
attention of ordinary observers as they
pass through them on the railway train
TO and from Olympia. To the trained
profound interest. but the attempt to solve
the problem of their history involves
many difficulties. For the last twenty
years they have been studied with more or
less care. Several theories have been pre-
scented which require mention here.
tumuii were built by fish while the land
was submerged in comparatively still
water seems Improbable from their physi-
cal structure. Fish, forming heaps for
breeding purposes would not pack to-
gether sand, gravel and cobbles. as in
these large mounds. 1t has been sup
posed by some that the Indians con-
structed them for burial places. or to clear
the land. Ii for burial places there should
be found remains of some character to in
dictate the fact. IL to clear the land for
agricultural purposes. why heap the earth
with the cobbles2 Again, Why take so
much trouble, involving a vast amount of
labor (which is not accordant with the
indian character), to clear the stony land,
b mill If liz Al
already quite clearg Others have sug-
gested that they were raised as founda-
tons for huts on q wet SOIL" The charac-
ter of the soil of the mounds, and of the
surrounding region preciudes this theory.
Ii would seem that no careful observer
can entertain either of the above views
The remaining theory, and the only one
which commands serious thought, il that
of Prof Joseph lie Conte, of California,
whose opinions should always be APP
preached and viewed with the highest
respect. He says, referring to the prairie
tracts, often called everglades. on which
the tumuli are situated:
These are doubtless old bottoms of
Puget sound, made dry by elevation. They
are covered with drift soil. These grassy
prairies are covered as thickly as possible
with mounds. about three to four feet
high and thirty to forty feet in diameter
There are probably millions of them. The
general appearance is that of almost per-
feet regularity Of size and shape The soil
of the mounds is rather fine drift, with
pebbles not larger then = pigeons egg. The
intervals between the mounds are strewed
with larger pebbles. The mounds are oc-
cupied by ferns. the intervals only by
grass. These treeiess spaces are called
mound prairissi Erosion re-
moves the finer top soil, leaving II, how
ever. in spots. The process once COM
menced. weeds, shrubs and ferns take
possession of these spots as the better
soil, or sometimes as the drier soil, and
hold them, and by their roots retard the
erosion there. In some cases departing
vegetation-a vegetation gradually de-
stroyed by an increasing dryness OF
climates an important condition"
Prof. lie Conte argues that the agency of
erosion must account for these mounds
lie starts with the idea that these tracts
ARE doubtless old bottoms of Puget sound.
made dry hy elevation" Did subseouent
erosion take places II so, II would appear
that the newly-eieyased plain was com
paratiyely smooth, surface stratum of
the same material as the present tumuh
being quite evenly distributed over the
entire area. Then erosion began, etc, as
above quoted Al this juncture pause to
point cut what seems a grave error in at
least one Of fEof lie Conte's afhrmations.
Ii would seem that be could not have per-
sonaily examined these tumnli, or at least
with care. He says; The soil OF these
mounds is rather line drift, with pebbles
not larger than 4 pigeons egg. The inter-
walls between the mounds are strewed with
larger pebbles." Instead, the tumuli con-
tain as large pebbles and cobblesiones as
those strewed between them. They range
from the size OF 3 pigeons egg 10 three,
fvsa -. h 4 n