Sujjerior 3Iississi2rplan in 3£issovri ami Arkansas. — Xei/es. 91 
It is now prett_y well established that ever since the earliest 
times, from the period when the North American continent 
first began to raise itself above the boundless sea, the Ozark 
region has been a district of constant movement. 
In the Carboniferous rocks which are exposed in almost con- 
tinuous section for nearly 300 miles along the Mississippi 
river the records of a number of oscillations have been recently 
made out. Immediately preceding the deposition of the 
Lower Carboniferous there was certain slight uprisings. 
Notable warpings of the earth's crust also took place at the 
beginning of the St. Louis, of the Kaskaskia and of the Coal 
Measures. The idea of a line of unconformity existing at the 
base of the St. Louis was first brought out by White. It has 
later also been suggested by Williams for Arkansas. At the 
top of the St. Louis exists the most prominent disparity in 
sedimentation, one only approached b}^ that at the base of the 
Coal Measures. Along the line of the present Mississippi 
river the shore line moved rapidly southward far beyond any 
point previously reached and littoral deposits were laid down 
below the mouth of the Missouri. A similar sequence of 
events appear to be disclosed in southwest Missouri. 
GLACIAL NOTES FROM THE PLANET MARS. 
By E. W. Claypole, Aki-on, Oliio. 
In connection with the much discussed Glacial era of our 
planet's history it would be of great interest to obtain definite 
knowledge of the possibility or reality of similar conditions on 
some other planet in our system. Nor does such knowledge 
seem altogether unattainable, though one planet alone thus far 
has afforded the slightest prospect of success in the effort to 
secure it. Mars has, ever since telescopes of sufficient power 
were first turned to his disc, presented to the eye appearances 
so strongly suggestive of that which our earth would present 
to a Martian astronomer as to inevitably suggest a compari- 
son, if not a resemblance. It is indeed difficult to avoid the 
conviction that the white masses on the poles of Mars as they 
emerge from their long winter ai'e really snow-caps. Their 
constant occurrence, their regular seasonal diminution during 
the past two hundred years as the poles alternately come out 
into the strong sunlight, and the total disappearance of one of 
