WOODWORTH: GEOLOGICAL EXPEDITION TO BRAZIL AND CHILE. 41 
IV. OUTLINE OF THE GEOLOGY OF SOUTH BRAZIL. 
For the, understanding of the relations of the Permian glacial 
deposits of south Brazil it is proper to give a résumé of the geological 
structure of the country. Passing over the pioneer work of Lieut. 
Colonel Wilhelm L. von Eschwege, whose writings are lithological 
rather than geological, the main outlines of this structure are to be 
found in the publications of Dr. Orville A. Derby and his associates, 
Dr. J. C. Branner’s résumé in his Geologia elementar, and in Dr. I. C. 
White’s Report on the coal area. In this résumé the observations of 
the writer have been allowed to a limited extent to enter into the 
interpretation of certain features of the region. 
The formations which enter into the structure of this part of Brazil 
may be grouped in the following terranes:—1. The Pre-Devonian 
or igneous and metamorphic belt of the coast including the Serra do 
Mar region, frequently classed as Archean. 2. The Devonian 
including the sandstone cuesta of the Serra das Furnas and the over- 
lying fossiliferous shales of Ponta Grossa in the state of Parand. 3. 
The Permian beds, including conglomerates, tillite beds, as well as 
sandstones and shales, the latter coal-bearing in the south. 4. The 
Triassic sandstones and trap sheets; the latter making the escarpment 
known as the Serra Geral and its topographical equivalents elsewhere. 
5. The Tertiary fresh-water deposits of the upland and possibly along 
the coast. 6. The Recent deposits along the coastal border now 
slightly elevated. | 
The Pre-Devonian Terrane-— The Pre-Devonian belt is here so- 
called because it comprises a complex of igneous and metamorphosed 
sedimentary rocks unconformably overlain by the westward dipping 
Devonian sandstones and shales of the upland, as yet the oldest known 
fossiliferous group in the region. The use of the term Archean or 
Pre-Cambrian for this complex seems at present inadvisable because 
of the possibility that certain of the metamorphosed clastic members 
of the series may be of Lower Silurian (Ordovician) or Cambrian age 
analogous in their structural relations to those of these ages in the 
metamorphic belt of the Piedmont terrane of the Atlantic slope of 
North America. 
In the latitude of Rio de Janeiro this belt of complex rocks includes 
the elevations known as the Serra do Mar and an inner line of moun- 
tainous relief known as the Serra da Mantiqueira. Gneiss of unde- 
termined origin appears to be the most ancient member of the region 
