woodworth: geological expedition to brazil and chile. 85 



Permian boulder-beds of Brazil I have set forth the evidence for the 

 existence of glacial discharge of debris at or near sea-level. The 

 occurrence of boulder-beds, presumably likewise of glacial origin, in 

 central Argentina is supported by the finding of tillite in Permian beds 

 on the Falkland Islands. These occurrences practically complete 

 the evidence that the Permian glacial traces occur on all lands outside 

 of the Antarctic circle in the Southern Hemisphere from shore to shore 

 of the Pacific Ocean. In South America the evidences exist from the 

 tropic of Capricorn southward to 52° S. L. They occur in South 

 Africa coextensive with the sediments of the time. In Australia they 

 occur over a vast area in the eastern part of that continent and in 

 Tasmania. It is now apparent that no shift of the polar axis in 

 Permian time will bring these evidences of glaciation into a better 

 circumpolar distribution than they now display.^ Thus those hypo- 

 theses which attempt to account for Permian glaciation by a shift of 

 the earth's axis of rotation have not been called for by any facts which 

 we now possess. The discovery of tillite in the latitude of 52° S. 

 diminishes the difficulty of the climatic problem by removing the 

 supposition that the glaciation was dominantly a subtt'opical affair. 

 The general absence of existing land in the Southern Hemisphere in the 

 latitude of the Falkland Islands probably accounts for the present 

 lack of signs of Permian glaciation in high latitudes. The Antarctic 

 continent is too little known as yet to premise what evidences future 

 explorations may bring forth. The facts upon which the Permian 

 glacial period rest still come largely from the Southern Hemisphere, 

 where at present the ratio of area of land to sea is so small. 



In the Northern Hemisphere the Permian glacial deposits remain 

 most typically de\eloped and best known in the subtropical region of 

 India; in the Salt Range and Talchir districts. But traces of ice- 

 action in high latitudes are not wanting and are coming continually 

 to light with the more critical diagnosis of the conglomerates of the 

 late Palaeozoic terranes. The Permian breccias of I^ngland regarded 

 by Ramsay as of glacial origin as early as 1855 appear to be now 

 accepted as such by English geologists. 



These traces occur in Latitude 53 N. A. Julien supposes the coarse 

 breccias of the Carboniferous in France to be of glacial origin, and 

 Kalkowsky attributes to glacial action a pebbly shale among the 

 Carboniferous rocks of the Frankenwald. These occurrences in 

 Europe pointing to some kind of ice-action if not in every case to the 



' Halle draws the same obvious conclusion from his discovery of the tillite on the 

 Falkland Islands. 



