4f)8 THE CRETACEOUS AND TERTIARY GEOLOGY 



by Mr. Derby in his article published in the Archives do Miiseu l^acional, Yol. IV, 

 for 1879 (published in 1881). These are horizontal beds exposed in the isolated hills 

 which extend along the left bank of the river from near Piranhas to Itaparica, but 

 they form more continuous chains from the serra de Tacaratu toward the interior, 

 while what ajjpear to be plateaux of the same rocks stretch away to the south of the 

 river also. In the immediate neighborhood of the river they are continuous from near 

 the mouth of Pajeu to Itajiarica. Above Pajeu, hills, apparently of these same rocks, 

 stand back fi-om the river and overlie the gneiss. These beds contain silicified wood 

 in abundance, besides a few other fossils. At a place called Atalho, fossil cyprids, 

 bones, teeth, and scales of fishes and of i-ej^tiles have been found. At Caissara several 

 leagues further up the river these beds occur again. 



The only determination of anj- of these fossils made by Mr. Derby was that of 

 scales of Lepidotus. He ventures the opinion that they are secondary and prob- 

 ably cretaceous, resembling somewhat the fi'csh-water cretaceous of Bahia. 



I regard the discovery of these dejiosits by Mr. Derby as one of great import- 

 ance in the study of the mesozoic geology of Bi-azil, for this locality seems to furnish 

 the facts necessary for the determination of the relations between the coastal beds of 

 the Sci'gipe-Alagoas region and the interior, and somewhat more elevated, beds of 

 Ceara. 



JRio Purus, Valley of the Amazonas. — The only unquestionable cretaceous de- 

 posits thus far known in the Amazon valley are on the Rio Aquiry, an afHuent of 

 the Rio Purus. These deposits were discovered by Chandless and are very briefly 

 described by him in an ai'ticle published by the Royal Geographical Society, Yol. 

 XXXYI, p. 119 et seq. The Aquiry enters the Puriis on the right in latitude 8° 45' 

 South, longitude G7° 23' "West. From the mouth of this stream to 11° South latitude 

 the water, when low, uncovers rocks in the middle of the stream, in which fossils are 

 Jbund. Yertebraj from these beds were seen by Agassiz at Manaus, and he pro- 

 nounced them to be those of Mosasaurus. Nothing is known of the general charac- 

 ter or extent of these beds. The theory that the cretaceous outcrops around the rim 

 of the Amazonian basin is not supported by any known facts. 



CORRELATION OF THE MESOZOIC OF THE COAST AND THE INTERIOR. 



Owing to the lack of knowledge of details a very brief discussion of the rela- 

 tions of the mesozoic beds along the coast with those of the interior is undertaken 

 with much hesitation. Indeed, were it not that this subject has already been touched 

 upon by Mr. Derby in such a manner as to lead geologists to suspect that we have 

 here unusual and very peculiar conditions, it would not be attempted at all. 



