186 Trans. Acad. Sci. of St. Louis. 
of wind-borne dust derived from the adjoining deserts. 
In the case of the larger example noted it is not to be 
inferred that since the clays and sands have such an 
enormous thickness, the waters were in the beginning at 
least of the same depth, but rather that the arm of the 
ocean and afterwards the inland sea was always very 
shallow, and that as the area was filling up with the sedi- 
ments the waters continued to rest on the surface of the 
basin rising with the rise of the bottom. 
In the phenomena connected with the filling of the 
Coon Butte lakelet by ‘‘lake deposits’’ is probably to be 
found the key to the entire mystery of the formation of 
the vast Western American ‘‘F'resh-water Tertiaries.’’ 
Lower Meteoric Zone im Coon Crater.. The bed of 
coarse materials lying immediately above the basal mem- 
ber of the section in Coon Crater is especially noteworthy 
on account of the meteoric fragments which occur so 
abundantly. This is at a depth below the floor of the 
crater of about 600 feet. Its formation appears to rep- 
resent an episode when eolic agencies had full sweep 
as at the present time, when concentration, as it were, 
of the large and heavy rock-fragments was going on 
through the exportation of the finer soil materials. So 
soon as a sporadic ‘‘cloud-burst’’ chanced partially to 
fill the crater, lake conditions prevailed and the process 
of residual concentration through deflative influences 
ceased. 
As will be more specially noted hereafter meteoric falls 
were probaly not more frequent during the time repre- 
sented by this zone, than during any other period of 
equal length. In the one case the finer soil particles were 
constantly removed, while in the other they were rapidly 
deposited. 
Mineralogie Composition of Canyon Diablo Meteorites. 
The Canyon Diablo meteorites have been described 
by many writers. Since the first announcement of their . 
