298 American Geologist. ^^y- i^os 
submerg-ed areas and insures a less luxuriant late growth, — 
unless the snow-fall was less than average. On the other 
hand a heavy fall of snow may be carried out by degrees in 
long time if south winds keep the rivers open, or open them 
early, and "chinooks" make winter visits to the snow fields. In 
the present year the ice broke up at St. Joseph on the last day 
of February and the stage of the river increased four feet in 
twenty-four hours, since when the excess of snow is going out 
in March. And the March winds are denied access to profes- 
sor Shimek's poor little source of supply for the double range 
of stately bluffs. It might also be considered doubtful if the 
most extreme stage of high water was of regular annual oc- 
currence. 
A reasonable search for the "sand-dune areas" in the vi- 
cinity of St. Joseph has not met with success, if they are to be 
identified by any similarity to the sand dunes of northwestern 
Nebraska or New Mexico, or those of Holland. If there is a 
resemblance anywhere it is only in the loose surface soil, of 
ieolian origin, that often caps the hills and covers slopes to a 
depth, usually not much greater than the length of grass roots, 
or fills sheltered depressions. Dunes might equally well be 
sought along the Rhine or on the banks of the swift-flowing, 
yellow Yangtse-kiang, where its loess deposit is extending the 
Chinese coast line and driving back to sea. 
The river bars having been credited with a lavish generos- 
ity in contributions to bluff building so greatly in excess of 
their visible available means, it may be acceptable if they are 
cited to show that where the floods have had greatest influence 
the areas so affected are not rendered at all unfit for such plant 
life as snails require. It is a fact well and positively known to 
dwellers on the Missouri river that in an incredibly short 
time after the surface of the bar becomes exposed there springs 
up a thick covering of willows and succulent plants which de- 
velop with extreme rapidity. If the floods pass early in the 
season, the willows forni dense thickets, or "brakes," that shel- 
ter the tender undergrowth from the summer heat and protect 
the bars from seolian erosion until swept away by the next sea- 
son's flood. The bars, accordingly, when so covered might be 
expected to retain a quantity of dust brought to them 
from other sources. If however, the river maintains a 
