46 University of California Publications in Geology [Vol. 13 



bearing stratum about six feet above beach-level, at point where cliff 

 begins (and is perhaps 20-25 feet high) on approaching the town of 

 La Jolla from the north." 



This ulna is not distinguished from that of other members of the 

 genus Phoca now found on this coast by any sharply marked char- 

 acters except that it is somewhat larger. The proximal portion of 

 the shaft is wider, and the bone itself is very light and porous. The 

 upper surface of the olecranon process is slightly worn away but 

 no doubt was similar to that of Phoca. The interosseous border is 

 rounded and the shaft shows a tendency to narrow toward the posterior 

 border. The incisura semilunaris (greater sigmoid cavity) for articu- 

 lation with trochlea of humerus is relatively flattened and is much 

 larger than in Phoca, but the coronoid process does not differ in any 

 essential details from that of the latter. It is impossible to determine 

 the exact nature of the head of the ulna because it was broken away 

 in the field in removing it from the matrix. 



ANCESTRAL ODOBENIDAE 



One finds, on studying the literature relating to fossil Pinnipedia, 

 that considerable confusion has been caused by the description and 

 inaccurate determination of fragmentary material. Many of the 

 remains assigned by earlier writers to the Odobenidae have been 

 found on reexamination to belong to other groups of mammals. 



Among the early writers, the account of Monti 8 on traces of the 

 deluge is the best known. He gave an account of a fossil mandible 

 found near Bologna, Italy, which he thought belonged to a walrus, and 

 which he referred to as "Phoca dcntibus exseftis, Rosmari sive 

 Odobeni." Some years later it was discovered that this mandible 

 was that of a rhinoceros. About this same time another observer by 

 the name of Leibnitz made a remarkable conjecture in which he 

 attributed to the walrus many bones and teeth of mammoths found 

 in Siberia. Almost a century later the celebrated Georges Cuvier 10 

 gave Georgi 11 the credit of presenting evidence in favor of the 



s Monti, Jos., De monumento diluviano in agro Bononiensi detecto, dissertatio, 

 in qua permultas ipsius inundationis vindiciae a statu terrae ante et postdiluvianae 

 exponuntur. Bologna, 1719. 



8 Leibnitz, God. W. von, Protogaea, s. de prima facie Telluris et antiquissimae 

 Historiae vestigiis in ipsis Naturae Monumentis (edited by Chr. L. Se.heibner), 

 cap. 33-34. Gottingen, 1749. 



10 Cuvier, G., Eeeherches snr les ossemens f ossiles, ed. 4, vol. 8, pt. 1, p. 458. 

 Paris, 1836. 



11 Georgi, J. G., Geographiseh-physikalisehe und naturhistorische Beschreibung 

 des Russisehen Reichs, zur uebersicht bisheriger Kenntnisse von demselben, nebst 

 Nachtraegen, vol. 3, pp. 390, 591. Konigsberg, 1797-1802. 



