54 WARREN D. SMITH 
THE TERTIARY SEDIMENTS 
We have found in Luzon, so far, no sediments known with 
certainty to be older than the Tertiary. In Ambos Camarines, 
there is a brecciated sandstone, and a shale, which some have 
thought to be older, but fossil evidence is entirely lacking. In 
Ilocos Norte, on the Baruyan River, I found some outcrops of a 
very red brecciated jasper, which may represent a Jurassic forma- 
tion. I made thin sections of this rock, and, while I made out 
no definite fossil forms, Dr. Karl Martin of the Reichsmuseum 
in Leyden, who examined them, said he could distinguish the 
remains of sponge spicules, and fragments of radiolarians, and he 
was of the opinion that the rock was very similar to specimens he 
had found in the Moluccas and which he had called Jurassic. 
These are exceptional and isolated cases. The main bulk of the 
marine sediments of Luzon are Tertiary sandstones, shales, and 
limestones. ‘The sandstone is usually a fine to coarse-grained grey 
rock which is very impure, having, as a rule, more feldspar and 
ferromagnesian than quartz fragments. Just how thick it is, we 
have never been able to determine, through lack of good sections. 
It probably varies from 60 to 325 feet in thickness. The shales 
are bluish-black to light yellow, very fine-grained, and generally 
low in silica. There is every gradation between the sandstone and 
the shale. The shales lie over and above the coal seams at nearly 
all the outcrops. How thick these are, we do not know exactly. 
They usually are very thin-bedded and are not very consolidated. 
Above the sandstones we find a hard, white, crystalline limestone 
which contains abundant remains of foraminifera—the principal 
genus being orbitoides. Below, I insert Professor Douvillé’s 
classification of the Philippine Tertiary, as worked up from material 
which I furnished him in 1908. This table (Table II) may fairly 
well represent the stratigraphy of Luzon. The uppermost lime- 
stone is noteworthy for its purity, as it has been changed very little 
since its formation in the sea. Coral remains are very abundant in 
many parts of it, in fact at an elevation of nearly 5,000 feet in 
Benguet we find a fossil coral reef containing fragments of many 
species of coral, most of which are now growing in the China Sea. 
