EXPOSURES ALONG GREAT WESTERN RAILWAY 89 



10 meters deep, where exposed in the cuts, and bands of cobbles, many 

 of them 20 centimeters in diameter, run straight through the hills. 



The pebble bands are derived from quartz veins that penetrate the 

 schists along this part of the line. 



At Allianca station again (kilometer 97.2; elevation, 59.2 meters) the 

 rocks are decayed crystalline schists or gneiss with waterworn quartz 

 pebbles overlying them in places. The schists here contain much mica. 



From 300 to 500 meters beyond Allianca waterworn quartz pebbles 

 10 centimeters in diameter are exposed in the railway cut 7 or 8 meters 

 above the stream level. 



At Pureza (kilometer 107.6; elevation, 70.2 meters) are decayed crys- 

 talline schists, and beyond the station the undecayed rocks are exposed 

 in the bed of the stream. A 

 kilometer beyond Pureza there 



are waterworn pebbles at the ^Tf^^^^&^^ ^^^o^ j 



track level, and at Timbauba -^yj/e/a^ed/^^iJi^.// 

 (kilometer 118 ; elevation, l 



Figure 17. — Section on the Railway near Barauna. 



100.7 meters) largewaterworn 



quartz boulders are exposed near and west of the railway station.* Some 

 of these boulders are 20 centimeters in diameter, and are both suban- 

 gular and well rounded. The rocks in place at Timbauba are either 

 crystalline schists or gneisses. 



The terminal station of the railway at Timbauba is on the watershed 

 between the drainage of Rio Goyanna and that of the Rio Parahyba. 

 The country around is hilly, but the slopes as a rule are gentle, and most 

 of them are covered with cultivated fields to their very summits. There 

 was not time to ascend the higher hills ; as seen from the village, many 

 of them appear to rise to an even skyline a hundred meters or more 

 above the station, while above these rise several higher peaks. The 

 accompanying sketch is made from a photograph taken near the Tim- 

 bauba station. 



So little is known of the nature of the waters of Brazil that I give here 

 the analyses ordered made by this railway of waters taken at five different 

 points along its line. These analyses were made for the purpose of deter- 

 mining the availability of the waters for use in locomotive boilers, but 

 they contain information of much interest in regard to the amount of 

 total solids in the waters, and they show something of the character of 

 these constituents. These waters are from springs near the stations 

 named in the table. 



XIII— Bull. Gbol. Soc. Am., Vol. 13. 1901 



