OF THE SERGirE-ALACJoAS BASIN OF HI{A/.[L. 385 



Jacuruna. 



At Jacuruna, a slioit distance iiorth-cast of Maroiin along the estrada real lead- 

 ing to the village of Rosario, is an exposure of oolitic limestones containing a few 

 fossils. To the west of the Ponte de Sabao bridge, is a hill having outcrops of simi- 

 lar rock on either side. An exposui'c of limestone passes east and west through the 

 village of Kosario. In one place where this stone is quarried, a bed thirty-Hve feet 

 in thickness is exposed. The rock is oolitic and in lithologic characters strongly 

 resembles that of the Gambarobe quarry in Maroim. The uppermost ten feet forms 

 a massive bed. These beds dip at an anglo of twenty degrees S. 45° E. (direction 

 estimated). Between this point and Campo Redondo the country is low, these cre- 

 taceons rocks and their hills forming the southern boundary of the valley, while a 

 range of tertiary hills bounds it on the north. Soft, cream-colored, cretaceous lime- 

 stones underlie these tertiary hills as was shown in the i)its excavated, north of En- 

 genho Cami)o Kedondo in a search for coal or gold. From one of these pits, ten feet 

 deep, a few fragments of fossils were obtained, one of which, Camptonectes idacltus 

 "White, is desci'ibcd in Dr. White's "Paleontology of Brazil.'' 



Coqueiro. 



Most of the material collected at Coqueiro came from a single locality, a small 

 exposure in the estrada real within a few hundred yards of the engenho of this name. 

 The rocks here are sandstones of very uneven texture, being in some places hard, in 

 others soft, in some places fine grained, in others coarse and porous, while in otheis 

 still they contain a great many quartz and other pelibles. Among these pebbles arc 

 some of black quartzite resembling very strongly the dark quartzites found in situ in 

 the serra d'llabaiana. Owing to local variations in the character of these sandstones, 

 some portions of the beds contain no fossils, all of them, if any ever existed in such 

 places, having been lemoved by pei'colating waters. The most abundant fossils are 

 conchifers, Triyonia suhcremdatu being esjjecially plentiful, and these occni- for the 

 most part as moulds or casts, the shells having been entirely dissolved out. In some 

 of the finer-grained portions of the beds many impressions of small and delicate lamel- 

 libranchs are Inmnl, but llic rock is so {Viable that they can be exti'acted only with 

 great diflicully. The scarcity of gastero[)ods in tliese beds is somewhat striking. 



To the north of the engenho is a small (piarry in which the rocks arc very hard 

 yellowish sandstones, from which the fossils cannot be successfully removed. East 

 of the river (Sergifje), at a ])lace called Pocinhos, about seventN'-five feet of sand- 

 stone is exposed. This exposure also shows a wide range of material in its composi- 



A. p. S. — VOL. XVI. 2w. 



