OF THE SKRfilPE-ALAGoAS BASIN OF BKAZIL. IJSo 



EXl'OSUKES ABOUT MAKOIM. 



(^luinies have been opened in many plaeos in and about Maioim from which 

 stone has been obtained lor building walls and houses and iov paving the streets. 

 One of these quarries on the Avestcrn side of the town is known as the 2)edreira dc 

 Gambarobe. The rock at this quairy is a brownish giay limestone, more or less 

 oolitic, and contains some fossils, though the shells are usually broken and dilMcult 

 of extraction. Lamellibranchs, cephalopods, decapod crustaceans, echinoderms, and 

 occasionally very lai'ge gasteropods are found b^' the (piurrymcn. Many Ijits of fossil 

 wood are also found here, but all in a cluured condition. 



On the eastern outskirts of the town, and lying more or less in it, at a place 

 known as Aroeiia are several old, abandoned quarries in calcareous sandstones. 

 These beds contain many fossils, but the rocks are too hard to allow them to be taken 

 out in good condition. The dip here is generally toward the east at a low angle. 

 The fossils described by Dr. White from the Eiacho de Aroeira are all from a small 

 exposure in the bed of a wet-weather stream to the north-west of the quarries. At 

 this place the rocks are more sandy iliaii at the quarries rcfen-ed to, and sometimes 

 are hard as quaitzites. They lie directly beneath the beds exposed at the quarries of 

 Aroeira and dij) to the S. 80° E., at an angle of six degrees. In the lowest part of 

 the bed are fragments of the softer yellow lock which lies at a lower geologic level, 

 forming, with the sand, a kind of conglomerate. 



Ziustro. 



The richest locality for fossils found in the vicinity of Maroim is one known as 

 the Laslro, about two miles down thu river from the town, on the east side of the 

 stream, and just south of the Engenho da Praia. From this engenho the exposures 

 contiiuie for more than three miles along the hills that border the stream on the east. 



The fossils described by Dr. "White from this locality come from the border of 

 the mangue along the first three-quarters of a mile below the engenho. In this dis- 

 tance the rocks furnishing the Ibssils are mostly soft, decaying, cream colored to 

 brown, oolitic limestones, which, by disintegration, have left the fossils free. In 

 places the small i-ock fiagments aic so full of echinoderms that they can be picked 

 out like walnuts from their hulls. In some cases the material of the.se fossils is 

 changed to i)ure calcium carbonate, while in others the more compact beds of lime- 

 stone have the fossils silicified so that they can be perfectly removed liy the use of 

 acid to dissolve the limestone. 



The weathering out of the fossils at this place is hastened by the tides which 



