woodworth: geological expedition to brazil axd chile. 27 



surmounted the dissected trap plateau at an ele\ation of some 700 

 feet above the valley of the Rio Ponte alto. The broad ^•alIey of the 

 E,io Cachoeiras which next succeeds exposes a bed of sandstone in its 

 banks below which lies a trap sheet over which in turn it flows. About 

 ten miles north of the river we camped for the night near a frog pond 

 between two of the mule bridges which mark the approach to Coryti- 

 banos. 



August 31st. — An hour's ride from camp brought our cavalcade 

 again to Corytibanos, at which point we took the road northwest 

 towards Sao Joao en route to Porta da Uniao on the Iguassii. For 

 several miles along this route we traversed campos with a scattered 

 growth of the the araucarian pine and then of the Butia palm. One 

 deeply weathered trappean hill bore numerous lakelets or lagoas 

 bordered by tall tufts of grass. Blackened heads of trap rock 

 cropped out over the surface of the inosculating ridges which separate 

 these solution-basins. At noon we halted beside a small stream whose 

 milky waters were without apparent cause since it had not rained. 

 On resuming our march we shortly heard the roar of falls in the course 

 of the Rio Marombas on the left in the forest where the river tumbles 

 over the bedded traps. The river was crossed on a balsa or ferry, a 

 sort of raft supported by four or five wooden canoes. (Plate 17). 

 A forest fire was burning on the east bank of the river. After travers- 

 ing two deep valleys and a broad hill of dry campo we camped on 

 another small milky stream in a cattle country. The milkiness of 

 these small streams was possibly due to cattle wading in them. The 

 day was warm, and beetles, butterflies, and dragon-flies were out 

 fluttering over the muddy flats of a stream at noon. 



September 1st. — About an hour and a half after leaving camp this 

 morning, we came to the Rio Correntes which was forded on a trap 

 bottom. After proceeding for an equal length of time we crossed 

 another broad shallow stream with rapids, the Rio dos Patos, also on 

 trap. We followed up the right bank of this river in a northwest 

 direction until nearly noon when we came to a coboclo hut in the 

 forest, where a woman gave us directions. Our halt for breakfast at 

 the noon hour was beside another small sluggish milky stream. 

 Several of the solution-basin lakelets were passed during the fore- 

 noon. As the trail was not distinctly marked from the paths leading 

 from one hut to another in this forested region, much of the after- 

 noon w^as spent in seeking directions. A large forest fire at one time 

 was raging to the west of our position. Fires in the standing clumps 

 of dry dead bamboo burn with great rapidity. At length we entered 



