suddenly to the northwest almost at right angles to its former course and reaches the sea at Cottabato, the capital of the district of the same name. Before emptying into Illana Bay the stream divides into two branches, and Mount Timaco is situated on the island thus formed. This large insular river gives access to an extensive territory rich in timber, rubber, gutta-percha, and other forest products, though but little was ever done by the Spaniards to develop this fertile region.

The Agusan is the second river of Mindanao and the third of the whole Archipelago. Its basin is formed by the main mountain ranges of the island running almost parallel to each other, and it is fed by numerous streams, some of them having a considerable volume of water. The river rises to the east of the Bay of Dávao, its general direction is almost north, and it empties into the Bay of Butúan near a town of the same name on the north coast. In its course it passes through Compostela, Moncayo, Jativa, and Patrocinio, settlements of Christianized Manobos. It spreads out near the middle of its course into Lakes Cadagun, Dugan, and Sinanat. A little below the last-named lake the Gibon flows into it from the right bank. The stream is something over 250 miles in length and is one of the arteries penetrating into the island from the north.

The Agus of Mindanao, like the Pasig of Luzón, is a short stream, but is the outlet of the important Lake Lanao as the Pasig is the outlet of Laguna de Bay. It is situated in the north-central part of the island, and the lake, though surrounded by mountains, has many fertile plains around its shores and promises to be a place of no small importance.

Those who have journeyed through the Philippine Islands unite in praising their natural beauty. Their volcanic origin, their mountain systems with their broad benches marking various upheavals, the numerous streams, the rich vegetation creeping from the water's edge to the summit of the loftiest mountains, the level plains industriously cultivated by a patient people, the genial climate and abundant rainfall all combine in making a magnificent panorama of pictures unsurpassed anywhere.

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Chapter II.

GEOLOGY.

Geology of the Islands uniform-Formerly swamps and shallow seas-At one time a part of Asia-Volcanic eruptions-Uplift gradual-Coral reefs-Terraces-River deltas-Mayón Volcano-Taal Volcano-Volcanic centersTable of active and extinct volcanoes-Seismic foci-Earthquakes-Relation between volcanoes and earthquakes.

According to the latest available data the geological history of the entire Philippine Group is uniform. The post-Tertiary gradual upheaval is common to Joló, Mindanao, Luzón, and the intermediate islands, and descriptions leave little doubt that the Philippines belong and have long belonged to a single geological and biological province.

Prior to the Tertiary epoch the Philippines consisted of slates and igneous masses, the age of which is as yet unknown, as no fossils have been detected. These rocks are now to be found in the northern and eastern ranges of Luzón, and appear to be represented also by some limited occurrences in Cebú, and seem to form the walls of the goldbearing quartz veins of the Province of Surigao, in the north-eastern portion of Mindanao. They are doubtless in reality widely distributed, but in most localities are buried beneath more recent formations.

During the Eocene, or earliest Tertiary, the Archipelago must have consisted largely of swamps and shallow seas, perhaps not very different from those now existing in the same region. Limestones were formed at some distance from the coasts, shales and sandstones were laid down near the shores, and accumulations of vegetable matter grew in the swamps. These last were covered with mud, and, in the almost total absence of free oxygen, they were gradually converted into lignite, probably the most valuable mineral asset of the Philippine Islands.

At the close of the Eocene a great crumbling and upheaval took place, which was felt from Switzerland to the Philippines, and perhaps most of all in the Himalayas, where marine Eocene beds now stand at an elevation of 16,000 feet above the sea. In the Philippines the Eocene strata are frequently thrown into a nearly vertical position, and sometimes are actually overturned. In the Visayas the axis of upheaval trended a little east of north, corresponding to the direction of greatest extension of the

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