GENERAL AND ECONOMIC GEOLOGY 227 



The remains of extinct Pleistocene vertebrate animals are frequently 

 found in old marshes where excavations are made for watering places for 

 cattle. 



Economic geology. — Our present knowledge of the economic geology 

 of the state is confined to the limestones found in the Archean area of 

 the interior, the bituminous shales of the coast, and the structural fea- 

 tures favoring the finding of water in the area of the coast sediments. 



Crystalline limestone or marble is known at Ipueiras between Que- 

 bragulo and Palmeira dos Indios (Dombre 38), at or near Colonia Leo- 

 poldina (Galvao), and on the road between San t' Anna and Aguas Bellas. 

 It probably exists at many other places in the Archean area of the state. 

 Most of the lime used in Alagoas is made from corals taken from the 

 reefs along the coast. 



Coal has been reported from the vicinity of Paulo Affonso, but its 

 existence, either there or elsewhere in the state, is doubtful. 



The bituminous shales are confined to the coastal belt of Tertiary sedi- 

 ments. These shales are known here and there along the coast from Bica 

 da Pedra, just east of the city of Alagoas, to Eio Persinunga, at the Per- 

 nambuco frontier. It is quite probable that they continue southward 

 nearly to the mouth of Eio Sao Francisco, but they have not yet been 

 reported from that region. No attempt has been made to utilize these 

 shales, though a report was made on them many years ago. (See Red- 

 wood and Topley and Branner.) 



The area of Tertiary sediments is one in which water may reasonably 

 be expected — possibly artesian water in some places. 



Three-fourths of the state lies in the region of the Brazilian complex — 

 granites, gneisses, and crystalline schists — in which many minerals of 

 value are likely to be found. 



Geologic Map of Alagoas 



John C. Branner, 1910. — But one attempt has been made at a geolog- 

 ical map of Alagoas; that is by J. C. Branner and was published in con- 

 nection with an article, "The geology of the coast of the State of Alagoas, 

 Brazil,'^ which appeared in volume VII, number 1, of the Annals of the 

 Carnegie Museum in 1910. The map forms plate II of that paper. It is 

 on a scale of 1 to 1,238,095 ; it shows only the eastern part of the State. 

 Only four divisions of the geologic column are attempted : old crystalline. 

 Paleozoic, Estancia, and Tertiary. The Estancia beds are there called 

 Trias with a question. Later studies show the Estancia beds to be Per- 

 mian — some of them at least. 



