196 Annals of the Carnegie Museum. 



From Crato up to the top of the chapada and southwestward across 

 it only the Cretaceous materials are exposed. Its southern border 

 near Novo Exu is formed by a bluff of red sandstone one hundred 

 meters high; but at the base of this bluff granite appears and con- 

 tinues down to the village, four hundred meters below the tableland 

 Thence eastward the granite extends up the chapada slope to Geni- 

 papinho, jointing being well developed along the ravine which the road 

 ascends. In the eastern part of Genipapinho red sandstone overlies 

 the granite at an elevation of three hundred and thirty meters above 

 Novo Exu and seventy meters below the top of the chapada. On 

 crossing eastward and descending to Jardim only red sandstone was 

 seen until near the level of the town, where shale appears. In the 

 lower land, twelve kilometers southwest of Jardim, schist at its con- 

 tact with granite is exposed at a small dam site. 



Along the road north from Jardim to Crato and thence west to and 

 beyond Sant' Anna do Cariry only the Cretaceous beds are in evidence. 

 Gneiss reappears twenty-four kilometers northwest of Sant' Anna, 

 with steep southeast dip, and thence forms the hills to the west; 

 but the material is granitic near Assare. Some variation in texture 

 was observed thence northward, with strike swinging from southwest 

 to west. About eight kilometers southwest of Saboeiro a stream 

 crosses a small range through a gorge, in which a prominent ledge of 

 muscovite quartzite is exposed, dipping nearly vertically to the south, 

 and flanked on each side by schist. Thence to Saboeiro rock, which 

 resembles altered shale, is exposed in several places along the road, 

 and also in the public square at Saboeiro. In every place where 

 observed its dip, nearly vertical, is conformable with that of the schist 

 or gneiss. 



Pegmatite dikes are common northwest from Saboeiro, and the 

 usual variations in the texture of the gneiss are exhibited along the 

 valley of Rio Jaguaribe to Arneiroz. A small, isolated range eight 

 to twelve kilometers northwest of Saboeiro seems to be of granite. 



Serra de Arneiroz contains a thick ledge of muscovite quartzite which 

 is well exposed on each side of the wide canyon of the Rio Jaguaribe. 

 The ledge dips thirty degrees to the northwest and is flanked on each 

 side by schist (or gneiss?) with conformable dip. Gneiss is thence fairly 

 constantly exposed northward to Taua, with north to west dip, the 

 strike in this stretch swinging from west through southwest to south. 

 A dark, chloritic rock is crossed by the road for nearly two kilometers. 



