2 Dr. A. S. Woodward on some 



Bravard *, Doering f, Ameghino \, Burmeister §, and Stelz- 

 ner ||, of whom the first three consider that its marine fossils 

 indicate an Eocene or Oligocene age, while the two latter 

 place the formation in the Upper Tertiary. The latest 

 examination of its fish-remains is supposed to have proved 

 its equivalence or homotaxy with the Eocene formations of 

 the northern hemisphere ^[. 



Fortunately a considerable number of the Parana fish- 

 remains are the teeth of sharks, which may be supposed to 

 have had a very wide distribution in the oceans at the time 

 when they flourished. The evidence of geological age which 

 they afford may thus be regarded as of considerable value. 

 I therefore propose to record a few observations on the Elas- 

 mobranch fossils from the Parana collections in the National 

 Museum of Buenos Aires, the La* Plata Museum, and the 

 San Paulo Museum, which have been kindly lent to me by 

 Dr. Carlos Berg, Dr. F. P. Moreno, and Dr. H. von Jhering. 

 The loan of these fossils has also enabled me to identify a 

 small series of Parana fish-remains labelled by Bravard in 

 the British Museum. 



1. Raja Agassizi, Larrazet. 



1886. Raja Ayassizii, Larrazet, Bull. Soc. G6o\. France, [3] vol. xiv. 

 p. 259, pi. xiii. figs. 1-6. 



The large dermal tubercles of an extinct skate thus 

 described are still known only from the Parana formation. 

 One typical specimen in the La Plata Museum measures no 

 less than 0*088 m. by 0075 m. across, by 0'03 m. in 

 maximum thickness. 



2. Dynatobatis paranensis, Larrazet. 

 1886. Dynatobatis paranensis, Larrazet, loc. cit. p. 268, pi. xiv. figs. 1-4. 

 These dermal tubercles evidently belong to a member of 



* A. Bravard, ' Monografia de los Terrenos Marinos Terciarios de las 

 Cercanias del Parana' (Parana, 1858). 



t A. Doering, in Roca, ' Int'orme Oficial Com. Cient. Exped. al Rio 

 Negro,' pt. iii. (1882) p. 429. 



\ F. Ameghino, ' Contribucion al Conocimiento de los Mamiferos 

 Fosiles de la Repiiblica Argentina ' (1889) p. 14. 



§ H. Burmeister, ' Description Physique de la Republique Argentina,' 

 vol. ii. (1876) p. 219. 



|| A. Stelzner, ' Beitriige zur Geologic und Paleontologie der Argentiu- 

 ischen Republik,' pt. i. (1885) p. 139. 



^1 G. de Alessandri, " Ricerchesui Pesci Fossili di Parana (Repubblica 

 Argentina)," Atti R. Accad. Sci. Torino, vol. xxxi. (1896) pp. 715-730, 

 with plate. 



