72 University of California Publications in Geology [Vol. 13 



Very little is known of the pinnipeds inhabiting the ancient delta 

 of the Rhine and its affluents during the period in which the green 

 sands were laid down. Only one genus, Monotherium, is known, and 

 up to the present time it has been discovered only in the green sand 

 series in the Antwerp basin. Monotherium dclognii is based upon 

 too fragmentary material to distinguish it from Monotherium affine. 

 Therefore, since Monotherium delogmi has page priority, it is here 

 interpreted to include Van Beneden's 101 second species, Monotherium 

 affine, as well. Monotherium delognii, apparently, was nearly as large 

 as Mesotaria, and somewhat larger than all other pinnipeds so far 

 known from the Antwerp basin. Monotherium abermtum was slightly 

 smaller, though it must have been considerably larger than Mono- 

 therium maeoticum of the Black Sea. 



The Italian forms of this stage all belong, apparently, to one 

 species. Our knowledge of this form is chiefly the result of the 

 investigations of Guiscardi, 10 '- who described a well preserved skull 

 and part of a mandibular ramus from the bituminous limestone of 

 Mount Letto, near Roceamorice, in the Compartment of Abruzzi and 

 Molise, as Phoca gaudini. Simonelli 103 described a canine tooth simi- 

 lar to this species from the Island of Pianosa, which lies between 

 the Tuscany Archipelago and the island of Corsica. The Phoca sp. 

 indet. of Flores, 104 found in the Miocene limestone of Lecce, in the 

 Compartment of Apulia, is based upon the Phoca sp. of Costa. The 

 latter has been shown to be a cetacean and not a seal. The canine 

 tooth from a similar formation, at Vignale, in the Compartment of 

 Piedmont, described by De Alessandri 105 as belonging to Pristiphoca 

 occitana, may also belong to Phoca gaudini. 



A fractured left mandibular ramus from the calcareous sandstone 

 at Gozo, Malta, was described and figured by Adams 100 as Phoca 



101 Van Beneden, P. J., Bull. Acad. Boy. Sci. de Belgique (2), vol. 41, no. 4, 

 pp. 800-801. 1876. 



102 Guiscardi, G., Sopra una Foca fossile. Bendiconte d. Accad. Sci. Fisiche e 

 matematiehe, Naples, 9th year, fasc. 12. p. 207. 1870. Atti d. Accad. Sci. Fisiche 

 e matematiehe, Naples, vol. 5, no. 6, pp. 1-9, pis. 1-2. 1873. 



J03 Simonelli, V., Terreni e fossili dell'Isola di Pianosa nel Mar Tirreno. Boll. 

 R. Comitate Geologieo d'ltalia, Rome (2), vol. 10, nos. 7 & 8, p. 209 (footnote). 

 1889. 



i°4 Fl or es, E., Catalogo dei mammiferi fossili dell' Italia meridionale eonti- 

 nentale. Atti della Aceademia Pontaniana, Naples, vol. 35, no. 18, p. 40. 1895. 



los De Alessandri, G., La Pietra da Cantoni di Rosignano e di Vignale (Basso 

 monferrato). Mem. Museo civico di Storia Naturale di Milano e Soc. Ital. di Sci. 

 Nat., vol. 6, fasc. 1, pp. 17-18, pi. 1, fig. 1. 1897. 



los Adams, A. L., On remains of mastodon and other vertebrata of the Miocene 

 beds of Maltese Islands. Quar. Jour. Geol. Soc. London, vol. 35, pt. 3, p. 524, 

 pi. 25. 1879. 



