Evidence on the Deposition oi Loess. — Owen. 293 
of about twelve feet below the surface at an elevation of 160 
feet above extreme high water. There is no indication that 
the place could ever have been the bed of a pond, but it must 
have been the river-bank before the time of the formation of 
the upper terraces described by professor J. Ei. Todd, in the 
Reports of the Missouri Geological Survey, vol. x. An ex- 
posure half a block distant shows ripple marks at nearly the 
same elevation. The loess deposit is very deep here and rises 
by steep slopes above the valley of thie Missouri on the West, 
and a small permanent tributary on the north which has a well 
defined ancient valley of its own. While graders were work- 
ing" at Sycamore and Sixteenth streets in the summer of 1903, 
a large skeleton oif an unknown lizard-like animal was exposed 
and created no little excitement among those present. Some 
years ago mastodon remains were excavated at a point only 
a short distance to the northeast and at a slightly lower level, 
so no one would think of claiming that the region h!ad been 
continuously submerged, and supporters of the aqueous theory 
have not been thus inclined. The annual floods, then as now, 
necessarily attained their excessive stage during the short 
period in early summer required for melting the vast quantity 
of snow spread over the region to the north and the enor- 
mously extensive water-shed extending far into the mountains 
on the west and northwest. The balance of the summer gave 
ample tim'e and favorable conditions for the development and 
growth of snails on all high points, which were then exposed 
under moist conditions, while the streams continued to fill 
their valleys with the normal summer flow from the "great 
ice" and the more distant regions of perpetual snow. The sig- 
nificance of this western drainage in connection with loess dis- 
tribution and deposition may not as yet have received its full 
measure of attention. The wide extent of area and the alti- 
tudes of sources of contribution from that direction ofifer sug- 
gestions worthy of special consideration. The southeasterly 
direction of this flow must have favored a much heavier and 
more widespread deposition of sediment to the eastward of the 
current than on the west, the limit of its spread being deter- 
mined by the resistance met in the volume of flow from the 
northern ice fields. 
