— 315 — 
24°, of the species of the Patagonian formation and 
20°, of those of the Santa Cruz occur also in the Chilian 
Tertiary of Navidad. To these are to be added the already 
mentioned genus Amathusia, which is common to both 
localities, and the many corresponding species. The 
families represented in Santa Cruz are almost without 
exception also found in Navidad. 
Ziltel called attention to the relation of the Santa 
Cruz Tertiary with that of New Zealand and has named 
several identical species. Unfortunately I.do not have 
access to the literature bearing on the Tertiary fauna 
of New Zealand. 
The present contribution to the knowledge of the 
Tertiary fauna of Patagonia together with Philippi's 
excellent work on the Tertiary fauna of Chile and the 
works of Steinmann and Moericke will enable us in a 
large measure to work out the history of the molluses 
of the Magellan district. Many genera have here become 
extinct since the Tertiary times or, like Strüthiolaria, 
have survived only in New Zealand. We can show that 
the representatives of the genera Voluta, Trophon, Tur- 
ritella, Natica, Venus, Cytherea, Dosinia, Pecten etc. at 
present living in southern Patagonia and the Magellan 
District are the derivatives of species that represented 
these same genera in older Tertiary times. But it also 
occurs that genera that were represented in older Tertiary 
are also represented now, but by species or sections that 
point to a different origin. Typical Arca occur in Santa 
Cruz Tertiary but the only present representative of the 
genus (Lissarca rubrofusca Lam.) belonges toa different 
section and points from its distribution over New Geor- 
gia and Kerguelen Island to an antarctic origin of a 
later date. The genus Cardium. represented today in the 
Magellan fauna and Chile by a very small species was 
represented in both places during Tertiary times by 
large, heavy and by other species. The families that 
were already present in Tertiary times and which were 
