A RECONNAISSANCE FROM DAVAO. 507 but just after leaving Banglasan one or two small bowlders of a basic, igneous rock were seen. For lack of any positive evidence to the contrary it is supposed that these bowlders originated in the underlying conglomerate and had worked loose from the matrix on weathering and disintegration. The descent from the divide to the Agusan Elver was made along the bed of Banglag Creek. This stream is only about half a meter wide near its source, but is fed by numerous branching streams, so that in the 7 kilometers of its course to the Agusan it grows to a stream about 6 meters in width and more than a meter in depth. The descent is fairly uniform in grade, and the sides of the gorge it has eroded are high and steep, as far as the valley of the Agusan. The Banglag runs over a series of strata beginning with conglomerate and sandstone lying practically level near Hoagusan, then over fossiliferous clay beds striking N. 15° W. and dipping 35° northeast. These beds are in turn underlaid by. shale striking N. 20° B. and dipping towards the southeast, and in the Agusan Valley by a coarse, calcareous sandstone, which strikes approximately N. 60° E. and dips about 35° to the southeast. This last sandstone contains large fragments of marine shells in a calcareous matrix. No evidence of marked or recent earthquake disturbances were observed on the route followed by the party, probably because the subsequent heavy growth of underbrush has erased or hidden the scars and fissures that may have been caused thereby; however, the territory traversed is supposed to be a region of violent seismic activity. The Bev. M. Saderra Maso, S. J, in writing of the seismic center of the Agusan River states' "This focus is possessed of great seismic activity, as is evidenced by the long series of earthquakes observed and carefully recorded by the Jesuit missionaries of that region since the year 1890. In June, 1891, a violent earthquake was the beginning of a long and fearful seismic period. This earthquake produced most serious destruction to the houses and ground; fortunately owing to the wildness of the country, there was little loss of life or of property. The falling banks of the river dammed it in many spots. Long and wide fissures were opened everywhere, especially on the hills separating the Agusan Valley from the Hijo and Sahug Rivers, which empty themselves into the Davao Gulf. The earthquake lasted several minutes, and during this time, says an eyewitness, the ground was moving as the troubled sea. During the following months, or during more than a year, the earth trembled with more or less force every day. In June 1892, there was a second violent disturbance, shaking the same region and renewing the havoc of the preceding year. These two earthquakes shook the Island of Mindanao nearly from end to end, and were fairly perceptible in the eastern Visayas. "Since these dates small shocks have been more frequent in this region than in any other part of Mindanao. Their cause is probably geomorphie rather than volcanic. There are unmistakable signs that the southern coast of Mindanao, Volcanoes and Seismic Centers, in Census of the Philippine Islands ( 1903 ) 1 204.