PROCEEDINGS 
OF THE 
NATIONAL ACADEMY OF SCIENCES 
Volume 5 JANUARY 15. 1919 Number 1 
ON SOME FUNDAMENTALS OF PRE-CAMBRIAN PALEO- 
GEOGRAPHY 
By Rudolf Ruedemann 
New York State Museum, Albany, N. Y. 
Communicated by J. M. Clarke, November 26, 1918 
It is an established fact that the Archean basement complex (representing 
the Archeozoic era) has undergone not only complete metamorphism but 
also a world-wide intense folding which undoubtedly is a true folding due to 
world-wide diastrophism. The later Pre-Cambrian rocks (classed formerly 
as Huronian, then as Algonkian and more recently as Algoman, Huronian 
and Algonkian rocks, representing Proterozoic time) have escaped meta- 
morphism and folding in the interior' of North America but elsewhere have 
undergone like folding as the Archean basement complex and with few 
exceptions in the same sense; for example, in the eastern Canadian shield, 
where both are folded from the southeast (Adams). This world-wide folding 
of the Pre-Cambrian rocks stands in striking contrast to the localized fold- 
ing of the earth crust in all later time. 
Starting from this fact of the complete folding of the exposed Archean 
areas and on the proper inference that the entire Archean basement complex, 
and with it the greatest part of the Proterozoic rocks of the Earth, is like- 
wise folded, the writer has attempted a synthesis of the directive lines of 
arrangement of these Pre-Cambrian folds. 
In such an attempt there are to be excluded: 
1. All areas of metamorphic rocks which are either proven to be or sus- 
pected of being younger than Pre-Cambrian age; such as are found in Greece, 
Asia Minor, the Andaman and Antillean Islands (serpentines of Cuba, etc.), 
the gneisses of the Coast range, lower California, etc. 
2. All rocks of Pre-Cambrian age involved in Post-Cambrian folding, as 
those of North Africa, Spain, France, western Germany, the Alps, eastern 
Australia, etc. But it is to be noted here that even in these cases, keen ob- 
servers have often enough found that the Pre-Cambrian nuclei of mountain 
ranges retain an independent original direction of folding, and further that 
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