39G THE CEETACEOUS AISID TERTIAEY GEOLOGY 



relations have, as yet, thrown but little or no light whatever upon the age of these 

 particular beds. 



In the mind of one acquainted with the mesozoic geology of Brazil, this fact 

 stands forth prominently : that while Dr. White's conclusion that these beds are cre- 

 taceous, must be accepted, the fauna presents peculiarities of its own in the Jurassic 

 facies of the Sergipe-Alagdas fossils. Another peculiarity of this cretaceous fauna of 

 Brazil is that certain of the typical genera, as Dr. White says, if found alone, would 

 be referred to the tertiary. It may be due to the incompleteness of the collections 

 made, but as far as we know these tertiary forms, Fusus, Murex and Phorus,* occur 

 only in the Pernambuco and Para collections, and not a single example is reported 

 from the Sergij)e-Alag6as basin ; whHe, on the other hand, not one of the Jurassic 

 forms is reported from the Pernambuco or Para beds. 



Thus far the writer has spoken of the mesozoic beds of this region as a whole. 

 Let us now ascertain, if possible, whether or not both Jurassic and cretaceous beds 

 exist here, and whether this apparent mingling of faunas may not be due to bad 

 collecting. 



'&• 



The StratigrcqiTdc delations of the Mesozoic Beds. 



The general relations of the rocks of the separate groups are shown in the sec- 

 tion through Itabaiaua, and it only remains to indicate the relations of the mesozoic 

 beds to each other. The details of these relatigns throughout have not been determined 

 with any degree of satisfaction, the time spent in the province having been taken up 

 entirely either in hasty reconnoissance or in collecting fossils. In the few more import- 

 ant instances in which these relations are known they are shown in the accompanying 

 illustrations. In view of the very interesting departure of the fauna of this group 

 from what would be regarded as a typical cretaceous fauna, the lack of detailed 

 information upon this subject is the more to be regretted. 



In Prof. Hyatt's paper upon the cephalopods of this region, no definite locality 

 is mentioned for these fossils than " the cretaceous beds at Maroim." I learned 

 from Prof. Ilartt subsequently that this collection was taken, almost entirely, from 

 the paving stones in the streets of Maroim. Now the quarries from which these 

 paving stones came are so numerous and at such different horizons, that these fossils can- 

 not be located stratigraphically, and ibr this reason, no valuable paleontological deduc- 

 tions can be made from them in determining the faunal characteristics and relations 

 of the separate beds in the vicinity of Maroim. 



♦This statement is made solely upon the authority of Dr. White's opinion as expressed in his " Contributions to 

 the Paleontology of Brazil," p. 17. IJut inasmuch as Fusus, Murex and Xenophora (Phorus) hegiu in the cretaceous 

 or earlier, it seems to be of doiibtliil value. 



