50 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
the Devonian sandstone cuesta in the Serra das Furnas and by the 
Serra da Paranapiacaba. 
That this gentle broad warping of the Post-Devonian strata is of 
Post-Permian date is shown by the sinuous trend of the outcrops 
of the Permian terrane. That it is Post-Triassic is also indicated 
by the down bending of the trappean sheets in the syncline on the 
south. Precise evidence of a local nature is apparently lacking to 
demonstrate how long after the completion of the local Triassic 
section the deformation was produced. ‘The dislocation of the Triassic 
Newark beds of eastern North America in presumably early Jurassic 
time would lead us to admit that the deformation of south Brazil 
may have taken place at this time. For topographical reasons set 
forth in the account of the physiography of this region (p. 99) it 
seems that this type of deformation took place in Pre-Cretaceous times. 
A Jurassic date for the deformation thus appears the most probable one. 
Summary of Geological History of the south Brazilian Plateau.— 
From this brief account of the geology of the south Brazilian plateau 
it appears that, long prior to the Devonian period, the region passed 
through a series of changes registered in the occurrence of igneous 
and metamorphosed sedimentary rocks as yet little understood. At 
least one series of sediments now slates and limestones involved in the 
complex may be the equivalents of the Ordovician or Cambrian strata 
but fossils are wanting to prove the age of these beds. The basal 
Devonian sandstones resting on the eroded edges of these meta- 
morphosed and intrusive rocks can only be interpreted as evidence 
of land conditions in the epoch preceding the Devonian and hence 
in the Silurian (Upper Silurian of Murchison). The Devonian sea 
transgressed the area and continued depositing sediments through the 
middle of that period. Whether deposition took place in the Upper 
Devonian is not now clear. The Carboniferous period was so far as 
the records go one of land denudation in which most of the Devonian 
was swept away. The extent of this denudation is such as to render 
it probable that higher Devonian beds originally overlay the Middle 
Devonian shales of Parana. 
True Carboniferous deposits appear to be wanting in the area, such 
strata as may have been referred to this epoch belong rather to the 
basal Permian. 
The Permian is characterised by a series of mainly non-marine 
formations laid down at or near sea-level with locally well-developed 
beds of tillite indicative of a glacial period. Elements of the Gloss- 
opteris flora have been found in Santa Catharina in shales which carry 
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