EDITORIAL. 



89 



by Mindoro on the west, Luzon on the north and northeast, Masbate on 

 the east, and Panay on the south. The Eomblon group is more closely 

 related geographically with Panay. Ahella in his "Descripeion Fisica. 

 Geologica y Minera en bosquejo de la Isla de Panay" does not mention 

 any marble or schists. Similarly, Ferguson in his study of Masbate did 

 not find a formation similar to that of Eomblon. The writer in crossing 

 from Lucena to Atimonan in Luzon found a schist formation in the 

 eastern Cordillera of Luzon a few miles west of Atimonan, but there was 

 no marble associated with it. This schist is evidently older than the 

 main group of sandstones, shales, and limestones, which have been 

 folded and faulted, producing the mountain structure parallel with the 

 eastern coast of Luzon in Tayabas Province, and extending into Tayabas 

 peninsula. The geologic structure of Mindoro has never been studied. 

 The marbles and schists of Eomblon can not be safely correlated on 

 lithologic appearance and in the absence of fossils their age must for the 

 present remain unknown. 



ANALYSES OF THE MARBLE AND SCHIST. 



It has been proposed to establish a cement plant at Eomblon, and in 

 order to determine the adaptability of the materials available, the 

 marble and schist have been analyzed. The analyses made in the 

 laboratory of mineral analysis and ph3'sieal chemistry of the Bureau of 

 Science are given herewith. The marble supplies the requisite calcium, 

 and is very low in magnesia, which is an objectionable element, but the 

 schist is high in silica and low in alumina. Some surface clay is avail- 

 able which might possibly supplement the alumina of the schist, but 

 there is not a siifBcient supply to warrant the building of a cement plant. 

 Moreover, it would be necessary to ship fuel to Eomblon. Accordingly 

 the manufacture of cement at Eomblon does not seem feasible unless a 

 schist lower in silica and higher in alumina can be found. 



Average chemical analyses of RomMon marhle and Romblon schist. 



Constituents. 



SiOo 



AloOa 



FejOs 



CaO — 



MgO 



NajO 



K.O 



Loss on ignition- 



Marble. 



Per cent. 

 .10 



[ .17 



55.23 

 .45 



43.80 



Schist. 



Per cent. 



80.12 



[ 12. 56 



I 1.15 



.12 



.48 



\ 3,69 



2.14 



George I. Adams. 



81630- 



