I IO 
PATAGONIAN EXPEDITIONS : PALAEONTOLOGY. 
hatchen. The more oval specimens are fully identical with Philippi’s main 
figure of O. bourgeoisi. These specimens approach closely the Cape Fair- 
weather form in the triangular outline, moderate area, and medium size 
and thickness of the shell. 
23. Cape Fairweather; 23 double, 12 lower, 5 upper valves. 
The characters of this form are given above. Crenulations of the mar- 
gin, close to the area (see pi. XVIII, fig. P), are shown in 14 upper 
valves (out of 28). 
Thus we possess from these 23 different localities 77 double, 76 isolated 
lower, and 35 isolated upper valves. Altogether, 153 lower, and 112 
upper valves are represented in our collection. 
Distribution : Darwin mentions this species from southern Patagonia 
generally, Philippi from Punta Arenas, v. Ihering from Santa Cruz and 
La Cueva (upper part of Patagonian formation and Suprapatagonian 
respectively); it has been found in the Pliocene Coquimbo beds of Chile 
(Moer.), and further in New Zealand, in the Oamaru and Pareora beds 
(Oligocene and Miocene) (Zitt., Hutt.). 
Affinities: Moericke has already compared this oyster with O. crassis- 
sima Lamck. from the Miocene of Europe, and there is no doubt a strik- 
ing resemblance between them in general appearance. Still closer appears 
the relation to that form called O. gingensis (Schloth.), especially when we 
compare the account and figures given of it by Hoernes (1870, p. 452, pi. 
76-80). Hoernes (p. 455) points out the close resemblance of O. gin- 
gensis and ingens . 
This type of oyster ( eras sis sima- ty p e ) — although not exclusively found 
in the Miocene — is a very characteristic feature of Miocene deposits. In 
older Tertiary beds this giant type is not found. 
35. Ostrea patagonica d’Orbigny. 
PI. XX, Fig. i°A 
1842 O. patagonica d’Orbigny, Voy. Amer. merid., v. 3, p. 33, pi. 7, f. 14-16. 
1842 O. ferrarisi d’Orbigny, ibid. 
1887 O. patagonica Philippi, Tert. Quart. Verst. Chiles, p. 215 (part.), pi. 
48, f. 2 (after d’Orbigny). 
1887 O. ferrar. Philippi, ibid., pi. 48, f. 5 (after d’Orbigny) (non text, 
p. 214). 
