224 The American Geologist. ^p"""- -'■'^*- 
continues down a slope, maintaining the general upland ap- 
pearance, character and thickness, no far-seeking is required 
for an explanation. The slope is an ancient one where summit 
conditions at some time prevailed and is often the termination 
of a spur at the outlet of a small valley or ravine where a trib- 
utary current has at all times kept an open gate-way through 
the bluff. Corresponding altitudes in a deep cut penetrating 
the bluff are either non-fossiliferous or the shells are small. 
At St. Louis and Water streets, where the street level is 143 
feet above extreme high water, a recent exposure presents the 
same homogeneous appearance, but the rains of two summers 
have eroded it in small furrows like perpendicular wrinkles and 
snail shells of the elongated spiral form are distributed through- 
out, the numbers increasing with the ascent as usual. If the 
depositing agency here were aeolian it would seem that the 
winds must have been strong and long continued, else we 
should recognize periods of interruption marked by a dark 
mixture of deep soil resulting from a rank growth of vegetation 
somewhat similar to present surfaces where accumulations ex- 
ceed erosive loss. Only wiry plants grow in the drought of a 
dusty wind and they offer scant support to snails. 
An example of the tenacious character of the loess is a 
conspicuous landmark at Fifth and Faraon streets where the 
remnant of a cut made in 1868 still maintains its perpendicular. 
The exposure is distinctly stratified above the street level of 
106.5 ^66t above extreme high water, although the laminations 
are not marked by variations in color. This uniformity of color 
is also observed in the strata exposed at the site of the South 
St. Joseph water-tower at an elevation of 270 feet above ex- 
treme high water. Extreme high water indicates the stage 
reached by the flood of 1881 when the entire flood-plain, from 
bluff to bluff, was inundated and is 816 feet above the sea. 
The only greater altitude in the vicinity of St. Joseph is at the 
main water-works seven miles further north. 
The necessary leveling for the construction of the tower 
left a perpendicular exposure of ten or more feet at the summit 
of the hill (plate X). The weathering of this shows hor- 
izontal strata with great distinctness, and snail shells ranging 
from the most minute to fully mature sizes are abundant. The 
two shapes common to the loess are represented, but the elon- 
