The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1893-10-31
THE FRAInIE MOUNDS.


SEATTLE. Oct. 80 1893.
To THE EDITOR: The theory in regard
to the numerous tumuli on prairies near
Olympia propounded by DR.. G. o. Rogers
in his article in the American Cecil
ogisi," from which you copiously quote IN
your paper OF today, will not, I think.
stand before the facts of the situation. 1t
has been clearly shown that the tumuli
are bas-reiiefs and are ell cut from the
same pattern. The material is stratified.
and an exposure of the surface shows the
strata to be horizontal and running
through all the mounds on the same plane.
The upper strata Of high mound are abb
sent in lower one, but up to their com.
mon altitude the strata of all are identical.
the same as they would be if the inter-
mediate spaces had been carved or eroded
away. This patent fact has been consid.
cred as eftectually disposing of all theories
oil up-buiiding by fishes, animals or man.
and would seem to dispose, also of all
theories OF dispositions by glaciers or other
agencies. The materials of glacial mo-
raincs are heterogeneous. The contents of
pot hole" on glacier might be measur-
ably stratified by the action of the water
In assembling the materials, but the strata
OF numerous pot holes" would not be
Identical, nor would their contents be the
same, as is the case with the tunuli near
Olympia. The theory of deposition would
seem, also. 20 be refused by the irregular
occurrence OF the patches of tumuli. Ifan
ice sheet existed, IL would have covered the
whole netghborkood and the tunuli would
have been co-extensiye with the influence
that created them. Besides there yould be
other evidences of the presence OF an ice
sheet. As q matter OF fact the patches of
tumulf are widely separated aud their Ar
rangement Is arbitrary as TO slope and ex-
tent. They exist on fat ground and on
rolling ground. Some praIries are wholly
and others only partially covered by them.
The theory OF erosion by winds is sun
ported by the facts that the mounds are all
carved from the same pattern. and, from
the presence IN the intermediate spaces. of
large cobhle stones, which were able 70 re-
siss the force that removed the lighter ma
terials- II is hard 10 conceive, however.
how certain parts of the pattern could
be cut away, and others of no more OBJ
stiaate materials left intact. Prot. Condor
accounts for this by the hypothesis that
the modern mounds were the ancient sites
OF cIumps OF small trees such as can be
seen IN the same neighborhood today. and
ihai the trees protected their immediate
vicinity while the winds eroded the omen
spaces. This theory must suppose a
nearly vertical current Of air blowing
against the surface like sand blast. with
saEaeens force 20 loosen and carry away
not oh'y sod IN the shape OF dust but peb-
o.ss IS sell. The wind does sometimes
eaoS against the surface OF the ground
acre row, and the time when il Is OBJ
sefFea 10 do SO Is seized upon By farmers
20 earn their slsshingS. much cleaner
burn being effected then than when tha
wlad blows upwards as a. ether times il
does.
Upon the whole. il seems to me that the
theory OF Prot. Condor is more consistent
vita known facts than any other yet ad-
Fsneed. The problem is very interesting
one ana II Is 20 be hoped that contro-
versy may arise which may induce further
physical research By scientists.
EreExR SExFlE