EXPOSURES ALONG ESTRADO CENTRAL OF PERNAMBUCO <V 



with quartz veins. Above this is a bed from 0.1 to 1.0 meter thick of 

 heavy waterworn pebbles, and above this is from 0.5 to 2 meters of soil. 

 It is to be observed that Victoria has an elevation above tide of 146 

 meters, and the gravel beds in the vicinity of the larger streams are pro- 

 visionally referred to fluviatile rather than to marine origin. West of 

 Victoria the rocks still appear to be more or less schistose. 



At Francisco Glycerio station (kilometer 64 ; elevation, 194.8 meters) 

 the railway cuts in red clay expose a few waterworn quartz pebbles 

 at the line of the junction between the soil and the hard rocks beneath. 

 In the vicinity of this station a rather flat plain opens northward, while 

 to the south and west rise mountains locally known as the Serra da 

 Russa, with a maximum elevation of 503 meters near the railway line 

 where it crosses into the valley of Rio Ipojuca. These mountains, how- 

 ever, are but the eastern and northern margin of the high and hilly 

 plateau of the upper Ipojuca drainage. West of Francisco Glycerio the 

 railway ascends the escarpment of the great plateau. Between Francisco 

 Gl} T cerio and Russinha, at an elevation of about 250 meters, the brilliant 

 red and yellow colors so characteristic east of this place appear to end. 

 West of here, also, the decomposition of the rocks does not seem to be 

 so. deep or so widespread. 



Immediately west of Glycerio the country is soil-covered, and more 

 than half of it is under cultivation. There are a few exposures of rock 

 on the hillsides and in the creek beds. There is a rather persistent but 

 in places pockety line of pebbles exposed in the cuts along this part of 

 the railway. It is generally at the junction of the soil and the unde- 

 cayed rocks beneath, and appears to be related genetically to the former 

 but not far removed drainage of the region. The individual blocks of 

 these gravels are often as large as a man's head. 



Along the next 3 to 5 kilometers east of Russinha the rocks look like 

 dark, very micaceous gneisses; they are cut by a few quartz veins and 

 are deepty decomposed. 



As one goes westward, Russinha (kilometer 72; elevation, 308.8) is 

 the last station on the railway before reaching the crest of the Serra da 

 Russa. A short distance west of that station the line crosses the water- 

 shed between the Rio Capibaribe drainage and that of Rio Ipojuca. 

 West of Russinha there are many deep cuts along the line of the road 

 that make excellent exposures of the geology ; some of these cuts are as 

 much as 30 meters deep measured on the upper slopes, and many of 

 them are 15 meters deep. There are, besides, several tunnels in which 

 the rocks are so solid that the tunnels do not require to be lined save at 

 their mouths. One tunnel was being lined, however, at the time of my 

 visit. Some of the rocks in these cuts are more evenly bedded, as if 



