Author's Catalogue. 127 
later Miocene and still continues, being marked by successive terraces 
and by elevated coral limestones. 
The author thus smiimarizes the probable geological history of the 
Philippines : 
"Summarizing the foregoing facts and inferences, it would seem 
that the geological history of the Philippines is something as follows : 
From early Paleozoic times onward an archipelago has usually marked 
the positions of these islands. Prior to the Eocene nothing definite 
is known of them, but further investigation will very likely disclose 
Paleozoic and Mesozoic strata there as in the Sunda and the Banda 
islands. During the Eocene it is probable that the lignitic series of 
Cebi'i was deposited, and the contorted indurated strata, which in 
other localities also carry black lignite relatively Tree from water, 
should be referred provisionally to this period. Whether the 
nummulitic limestone found at Binangonan is Eocene seems to me to 
be an unsolved question. After the Cebuan lignitic epoch a great up- 
lift and folding took place, and this may have been a detail of the late 
Eocene movement which so profoundly modified Asia and Europe. It 
must have brought about temporarj'^ continuity of land area between 
Borneo and Luzon. Somewhere about the middle of the Miocene the 
country sank to a low level. Many of the present islands must then 
have been far below water, while Luzon and Mindanao were repre- 
sented by groups of islets. Observations appear to suggest that the 
Agno beds represent the basal conglomerate formed at this subsidence. 
A slow rise began again during the later Miocene, and may have con- 
tinued to the present day without inversion, yet the actual distribu- 
tion of living forms is such as to give some grounds for believing that, 
at some intermediate period, the islands were a little higher than they 
now are, but sank again only to rise afresh. The diorytes and asso- 
ciated massive rocks, including their tufifs, may have made their ap- 
pearance about the close of the Paleozoic. The less siliceous of these 
rocks seem to have followed the more siliceous intrusions as a whole. 
The gold deposits, and perhaps other ores, are so associated with these 
massive rocks as to indicate a genetic relation. The neo-volcanic per- 
iod began as early as the highest Miocene horizon, and very prob- 
ably at the post-Eocene upheaval. If the semi-plastic marls of Cebii 
are all Miocene, the earlier andesitic rocks, at least, date back nearly 
to the great up-heaval. Among these rocks, also, there is sometimes 
a tendency for the basalts to follow the andesites, but the one dacite 
found at Corregidor is later than the andesites of that island. The 
relation of the trachytes to the andesites is not certain, but the sanidinc 
rock is probably the earlier. A very large. part of the neo-volcanic 
ejecta has fallen into water and been re-arranged as tuffaceous plains, 
ihe volcanic vents appear to me to occur rather on a net work of fis- 
sures than on a single system of parallel diaclases, and the volcanic 
activity is to be regarded ns a thermal manifestation of the energy 
of upheaval." n. h. w. 
