﻿224 



EVELANI). 



part at least, extrusive and intrusive in relation to some still older forma- 

 tion of which, so far, no trace has been seen. Five analyses of samples 

 of the diorite from various localities are as follows : 



Analyses of the Benguet diorite. 4 



Constituent. 



Moisture at 110° (M — 110°). 

 Loss on ignition (M-f 110°) 

 Silica (SiOo) 



Alumina (AUOj) 



Ferric oxide (Fe.iO :J ) 



Ferrous oxide (FeO) 



Calcium oxide (CaO) 



Magnesium oxide (MgO) .. 



Potassium oxide (K»0) 



Sodium oxide (Na»0) 



Total 



Per cent. 



0.37 



3.16 



49.89 



1.87 



2.61 



23.47 



10.75 



6.57 



.09 



2.01 



100. 79 



Per cent. 

 0.32 

 3.54 



51. 08 

 1.47 

 3.57 



25.30 



8.15 



4.12 



.22 



2.13 



99. 90 



III. 



Per cent. 



0.46 



3.24 



49.20 



3.64 



.84 



25. 00 



10.66 



6.76 



.06 



.76 



IV. 



Per cent. 



0.16 



.75 



51.48 



20.31 



6.24 



3.46 



8.86 



4.29 



2.07 



3.01 



100. 62 



Per cent. 



0.18 



3.24 



50.71 



4.74 



2.26 



20.64 



13.48 



4.21 



.18 



1.03 



100. 63 100. 27 



Number I represents the porphyritic variety from the "Middle Keef." 



Numbers II, III, are from the Antamok Eiver. 



Number IV is from Gold Creek. 



These analyses should be compared with the following ones, made 

 on samples from the Lepanto area on specimens of the "Mancayan 

 diorite" which probably were fresher: 



Analyses of the Mancayan diorite. 1 ' 



Constituent. 



I. 



II. 



III. 



IV. 



Moisture (—110°) - _ 



Per cent. 



0.50 



2.74 



50.67 



21.21 



11.31 



.21 



6.86 



4.10 



.10 



1.41 



Per cent. 



0.28 



1.38 



51.00 



18.01 



.23 



9.31 



8.89 



6.53 



.46 



4.42 



Per cent. 



0.38 



.70 



47.98 



18.94 



7.08 



3.98 



11.01 



7.06 



.44 



2.56 



Per cent. 



0.12 



2.26 



47.94 



21.96 



2.48 



3.42 



12.63 



6.83 



.19 



1.49 



Loss on ignition (+110°)- _ - - 



SiOo — - - . — - 



A1»0 3 _ - _ 



Fe.,0 3 _._ ._ — _ 



FeO - - — 



CaO . "- .._._.. .-_ 



MgO . - - 



K»0 - - - — 



Na*0 - 



Total _ _ _ 



99.11 



100.51 



100.13 



99.35 





4 Analyses Numbers I, II, III and V are by Dr. R. F. Bacon, and Number IV 

 is by Paul J. Fox of the Chemical Laboratory, Bureau of Science. 



5 Analyses of Mancayan rock are by Mr. L. A. Salinger, Chemical Laboratory, 

 Bureau of Science, Manila, P. I., 1905. 



