74 PROCEEDINGS OF THE PHILADELPHIA MEETING 



1. The generally centrifugal flow of surface air currents above the domes 

 of inland ice. 



2. The areas of relative calm over the central bosses of these ice domes. 



3. The gradual working up of the glacial blizzards and their abrupt termi- 

 uations in a sudden elevation of air temperatures (foehn effect). 



-1. The saturation of the air above the central areas of calm and the pre- 

 cipitation of snow or ice within the zone near the glacier surface. 



.">. The general paucity of other than wind-driven snow falling over the 

 outer slopes of the ice domes. 



G. The centripetal flow of upper air currents shown by the drift of clouds 

 and of volcanic vapors. 



7. The predominance of the cirri above inland ice, except at its margins. 



S. The centrifugal drift of the snow from the central areas of continental 

 glaciers and its accumulation in grabular form about their margins, and par- 

 ticularly at the base of outlet glaciers. 



In the four years which have elapsed since this theory was promulgated the 

 volume of evidence along most of these lines has been greatly augmented 

 through the publication of scientific reports on expeditions carried out before 

 the theory was published, but far more by the preliminary reports on new 

 explorations within the two principal areas. These expeditions are notably 

 the crossings of Greenland by De Quervain in 1912 and by Koch and Wegener 

 in 1913, and the Antarctic expeditions of Captain Amundsen, Captain Scott, 

 Lieutenant Filchner, and Sir Douglas Mawson. To the amplification of evi- 

 dence along the above designated lines there has now been added the revelation 

 of strong inversions of the atmosphere about the glacier margins and an up- 

 ward extension of the outward flowing air currents, made known by ascents 

 of kites and of pilot and registering balhxjns. The purpose of this paper was 

 to draw attention to this new evidence. 



Presented by title in the absence of the author. 



ORIGIN OF MONKS MOUND 

 BY A. B, CROOK 



(Abstract) 



Monks Mound, the largest of the Cahokia group of mounds, situated 6 miles 

 east of Saint Louis, has for many years been described by archeologists as the 

 "largest artificial mound" in existence. 



Twenty-five borings were made in the north and most abrupt side. 1. They 

 showed different strata at different elevations. 2. These strata agree with 

 similar elevations in the other mounds and with soil from the bluff 2 miles 

 away. 3. Fossil hackberry seeds (Celtis occidcntalis) and such gasteropods 

 as Pyramidula, Succinen, Heliciiia, and Pliysa are found in beds. 4. A study 

 of the physiography of the mounds makes clear that they occur along the 

 divide between streams, and that their arrangement and individual forms are 

 characteristic of the remnants of stream cutting. 



Chemical and mineralogical .study of the soil, as well as paleontological and 

 physiographical investigations, indicate that the mounds are the remnants of 



