20, 1 Smith: Pidatan Oil Field, Cotabato, Mindanao 33 
5. Zamboanga, river bank 2.5 miles north of Zamboanga, upper stratum. 
Murex capucinus Lam. L. 
Concerning these species, he states his opinion on pages 622 and 623: 
“As for Mindanao, it can not be demonstrated from specimens which have 
been investigated that Miocene strata occur there, for I have but a single 
species, Ranella raninoides Mart., which is known only in the Miocene. 
On the other hand, it is clear that there are upper Tertiary beds along 
the Agusan River. If it were permissible to assume that all the fossils 
of the list given above originated in equivalent beds, and their state of 
preservation makes this probable, there would be in all 10 species, 6 of 
them, or 60 per cent, still living; 4 species occur in the Miocene and the 
same number in the Pliocene; but of these last three are known only 
from the Pliocene. These are Latirus madiunensis Mart., Turricula ba- 
taviana Mart., and Murex verbeeki Mart. All this argues the occurrence 
of the Pliocene on the Agusan River, and in harmony with this indication 
is the exceedingly fresh appearance of the fossils at hand. 
“The same age finally may be ascribed to the fossils from the river 
Salac y Maputi in Mindanao; for although of the 6 species determined 
from this locality no fewer than 5 belong to the present fauna, yet of 
these latter 4 reach back to the Miocene and Pliocene and a single species 
Murex verbeeki Mart., is known only in the Pliocene. Of the deposit 
at Zamboanga nothing definite can be said as yet on the strength of 
the solitary fossil Murex capucinus Lam. 
“To the age determinations of Philippine fossils it is proper to add 
that their state of preservation resembles that of the Javanese fossils to 
a very remarkable extent—to such a degree, indeed, that the specimens 
from the two regions might easily be confounded. The same statement is 
true of the tuffs and marls in which they were embedded, and this accords 
with the fact that the younger massive rocks of the Philippines show an 
extraordinary likeness to those of the East Indian Archipelago.” 
The writer is in entire agreement with Martin’s assignment of the 
Agusan beds to the Pliocene and their analogues, the Banisilan formation, 
as well. The descriptions of Moody and Smith of the stratigraphic rela- 
tions of the tuffaceous sandstones at Banisilan yielding the above fauna 
to the conformably underlying coralline limestone indicate that the Bani- 
silan is upper Pliocene since the coralline limestone is largely composed 
of corals characteristic of the Malumbang formation of Pliocene age. 
Percentages given in Martin’s statement above are calculated on a total 
of ten species from four different localities and the number of forms is too 
small to be truly significant. The Turricula bataviana Martin occurs 
at Bureau of Science locality F1054 near San Rafael, Agusan River, 
where it is associated with a fauna containing at least from 90 to 95 
per cent Recent species. Without going into great detail, the writer’s 
judgment concerning the age of this fauna is strongly influenced by 
a recent study made upon a fauna obtained from the Vigo group of 
Miocene age which contained an astonishingly large number of Recent 
forms. The conclusions given in this paper are that the evolution of 
Gastropoda and Pelecypoda in the Tropics is far slower than in the 
Temperate zones and hence a different percentage scale in the Tertiary 
183677-—_3 
