304 REVIEWS 
Mississippian that their origin is often traceable to a beginning in fossils. 
The geodes are invariably found in or near joint planes and rifts along 
which waters have had easy passage. A large majority of the geodes in 
the Knobstone may be traced to an origin in a fractured crinoidal stem or 
brachiopod shell. In all the specimens described deposition of silica in the 
fractures has been preceded by a complete silicification of the fossil itself. 
The crystallizing force of the addition of silica in the fracture continues to 
rupture the fossil more and more which later forms a typical geode. 
The author maintains that the replacement of the original calcareous 
material of fossils by silica in siliceous pseudomorphs does not take place 
at the time of deposition of sediment, but rather that silicification proceeds 
as weathering advances. It has been observed that limestones yielding 
siliceous pseudomorphs contain in the unweathered portions calcareous 
fossils. The embedded part of the fossil is often calcareous while the 
exposed part is siliceous. From these lines of evidence he concludes that 
silicification of many fossils is a present process. Ca Ee 
Mineral Resources of the Philippine Islands. By WARREN D. SMITH, 
Chief of the Division of Geology and Mines. 39 pp., 6 pls., map. 
Manila, 1908. 
This bulletin marks the beginning of an annual statement of the mineral 
production of the islands. The plan adopted is similar to that of the U. S. 
Gas: 
The nonmetallic products are first considered. A low-grade, sub- 
bituminous coal, suitable as a gas-producer, is mined. It is abundant, but 
coal-mining is difficult owing to complex folding and faulting. Some of the 
mines are promising. A good quality of lime is manufactured at Binan- 
gouan. Raw materials for the manufacture of cement are abundant. 
The limestone is very free from magnesia. Mention is made of natural 
gas, petroleum, building and monumental stone, abrasives, gypsum, 
phosphates, sulphur, salt, magnesite, mineral waters, Fuller’s earth, mica, 
manganese, and precious stones. The brick, tile, porcelain, and pearl 
industries are of little importance. 
Gold is the only metal now mined to any notable extent. A profitable 
mine is worked in Benguet. Deposits of copper, silver, lead, iron, and 
tellurium occur, but are not actively mined. 
Production in 1907: gold, 4,540 02z., silver, 83 0z., iron, 436 tons, coal, 
4,545 tons. Cojo: 
