ne Ohio Naturalist, 



PUBLISHED BY 



The Biological Club of the Ohio State Uni'versity, 

 Volume XI. FEBRUARY, 1911. No. 4. 



TABLE OF CONTENTS. 



Stauffer— A Review of Literature on the Guology of South America 273 



Selby— The Blister Rust of White Pine (Peridermium Strobi Klebahn) Found in Ohio 285 



Griggs— Eupatorium Rotundifolium in Ohio 287 



Wells— Meetings of the Biological Club 287 



A REVIEW OF LITERATURE ON THE GEOLOGY OF 



SOUTH AMERICA. 



C. R. Stauffer. 



ARCHEOZOIC AND PROTEROZOIC (pRE-CAMBRIAn) 



The pre-Cambrian of South America is mainly limited to 

 three regions: 



(a) Guiana, including portions of northern Brazil and 

 southern Venezuela. 



(b) The highlands of eastern and southern Brazil. 



(c) Narrow strips in the Andes lying north of 40° S. latitude, 

 together wdth similar strips running north and east from the 

 main chain in northern Venezuela. These Andean strips may be 

 of much later age, but they have been referred to the pre-Cambrian. 



The first of these regions includes an area of more than 500,000 

 square miles of elevated broken land. It is separated from the 

 Atlantic coast by a 10 to 70 mile "wide strip of post-Tertiar}^ sands 

 and gravels, is (according to Crosby) bordered on the north and 

 west for a distance of 800 miles by the Orinoco River, and to the 

 south dips under Paleozoic and more recent sediments along a 

 line which Derby draws approximately "from the mouth of the 

 Amazonas, in latitude 1° N., to the confluence of the Rio Negra 

 and Rio Brancho, between 1° and 2° S. latitude."^ 



The rocks of this region Crosby has grouped together in 

 somew^hat the following manner: 



Pre-Cambrian 



(4) Semi-crystalline schists and marbles. 



Great unconformity 

 (3) Montalban series. Gneisses and schists cut by coarse granite 



dikes. Garnets common. 

 (2) Huronian series. Quartz porphyry and felsite associated with 

 various hornblende and slaty rocks showing distinct 

 bedding. 

 (1) Laurentian series (?). Granite and some syenite.^ 



1. Crosby, W. O., Proc. Boston Soc. Nat. Hist., Vol. XX, 1881, p. 484. 



2. Crosby, W. O., Loc. cit., p. 493. 



