1879.] - 10 '' [Devby. 



morpbic series to the Archean, and the non-crystalline series to the Lower 

 Silurian or Cambrian, a classification in which I but follow my esteemed 

 friend and teacher, the lamented Prof. Hartt. 



Going west from Curityba, at a distance of about thirty miles, an abrupt 

 escarpment, called the Serrinha, or Little Serra, is met with, rising to an 

 elevation of 1040 metres, or about 200 metres above the plateau of Curityba, 

 which it completely dominates. This escarpment extends across the prov- 

 ince in a general north-south direction, being, however, somewhat irreg- 

 ular and zig-zag towards the north, where it becomes, in a measure, con 

 founded with the higher lands of the Assunguy region, which surpass it 

 in elevation. In consequence of this it does not separate so completely as 

 in the south the various systems of drainage. 



This escarpment is composed, in the lower part, of the inclined meta- 

 morphic beds above described, capped by massive horizontal beds of coarse, 

 friable, white sandstone, which rise everywhere to the same level, but vary 

 in thickness from 20 to 100 metres, owing to the irregularities of the sur- 

 face upon which they were deposited. 



The Serrinha forms the eastern margin of the second region, the far 

 famed Campos Geraes. This is a vast grassy plain, extending westward 

 about 100 miles, with a gentle inclination towards the west, where the ele- 

 vation of the highest portions becomes reduced to from 850 to 900 metres. 

 The surface along the margin is almost perfectly level, but the innumera- 

 ble streams, fed by thousands of springs and by torrential rains, soon cut 

 themselves deep valleys, descending in the western portion of the region to 

 an elevation of 600 metres, rendering the surface more and more undula- 

 ting, as one enters the Campos. In a broad zone in the western part, there 

 are, in addition to the irregularities due to denudation, others of greater 

 consequence, caused by numerous immense dykes of diorite. 



The character of the rock changes also in going wesi ward, the sandstone 

 becoming finer and tending to give way to beds of shale, which occur 

 interstratified with the sandstone, in such a manner as to show that they 

 belong to the same formation. In general it ma}' be said that, in the west, 

 as a rule, the lower portion of the formation is composed of shales and 

 shaly sandstones, the shales in the extreme west becoming charged with 

 silicious and calcareous concretions, and containing a few subordinate beds 

 of a peculiar, silicious, oolitic limestone. This shaly portion is wholly, or 

 in part, overlaid by soft sandstone, which to the eastward is the predomi- 

 nant formation. The sandstone appears to cover the shales over the entire 

 region, but on this point I cannot form a positive opinion, before making a 

 detailed study of the fossils collected, as it is possible that, in the wooded 

 limestone region, I may have been deceived in regard to the identity of 

 the sandstone that occurs there, with that of the open campos, further east. 

 The rock is everywhere charged with pebbles, and often, in limited re- 

 gions, changes to a pudding stone or conglomerate. In a ravine near 

 Ponta Grossa, I found such a conglomerate, containing boulders a foot and 

 a half in diameter, of metamorphic rocks, such as gneiss, syenite, quartzite, 



