34 Annals of the Carnegie Museum. 



caudal fin of Number 114 suggests at first sight the figure of Mawsonia 

 minor, as given by Woodward, Quart. Journ. Geo!., LIV, 1908, 358, Plate 

 XLIV, a Brazilian Cretaceous fish. But that species is a Ccelacanth, with 

 imperfect or cartilaginous vertebrae, and it can have no real affinity with 

 this species, which is doubtless one of the Chirocentrid herrings. 



Age of Deposits at Riacho Doce. 



Judging from our knowledge of similar fishes among the existing species, 

 it is probable that the shales of Riacho Doce were deposited in an estuary, 

 and that their age is Lower Eocene, possibly but not probably Upper 

 Cretaceous. 



Most of the known species of Diplomystus are of later than Cretaceous 

 date. It is also noteworthy that in the Cretaceous about Bahia and about 

 Ceara, none of the species here noted from Riacho Doce were taken. 

 On the other hand, the species found at Riacho Doce are all unlike any 

 yet seen in the Cretaceous. All this would seem to show that the rocks 

 examined in the state of Alagoas are Eocene, while those about Bahia 

 are of the Upper Cretaceous. 



