82 NEW YORK STATE MUSEUM 



folding in the Precambrian basement complex. Such undisturbed 

 blocks are found in the Rocky Mountains, in Bohemia, Cambodia 

 etc. 



The large areas that are then left and that lend themselves 

 directly to our inquiry, are: the greater part of North America, 

 small regions of South America, eastern Europe, northern and 

 eastern Asia, all inner Africa and western Australia. The general 

 facts gleaned from these are complemented by those obtained from 

 the unfolded " islands " or blocks and the posthumous folds. 



The most important source of information for this inquiry has 

 been Eduard Suess's " Das Antlitz der Erde " where there is not 

 only a large store of information as to the directions of Precambrian 

 rock folding in various regions but where also the facts of the general 

 directions of Precambrian folding in Asia and eastern Europe are 

 clearly set forth. For North America, Van Hise and Leith's " Pre- 

 cambrian Geology of North America " and the folios of the United 

 States Geological Survey furnish the principal data. 



