380 



cox. 



The iron content of this sample is so large that the clay could not be 

 expected to yield a white product, but its physical properties, particularly 

 its plasticity, tensile strength and shrinkage are such as to make it useful 

 in the manufacture of colored wares. The clay does not crack in burn- 

 ing. In the future these deposits will probably be valuable, but the 

 outcrop indicates that the supply at present would be quite limited 

 without a laborious and expensive system of troughs and tanks. Such 

 operations would not pay except on a clay of the highest quality. A 

 limited amount of this clay could probably be mined and especially 

 because of its low shrinkage would be used to recompose other clays 

 which in some ways have more desirable physical properties. 



MAJAYJAY. 



The deposit at Majayjay is on Mangulila Creek about 30 or 40 meters 

 from its mouth where it empties into the Dalatiuan Eiver at an altitude 

 of 180 meters. It is 300 or 400 meters above the point at which the 

 Majayjay-Lucban trail crosses the Dalatiuan gorge. There is a large 

 amount of clay in sight. On the left side of Mangulila Creek the clay is 

 exposed in a bank 15 or 20 meters long and about 4 meters high. This 

 material is probably of sedimentary origin. I removed the surface and 

 thoroughly investigated the clay. It is very uniform in quality and 

 plasticity, free from grit and bluish in color when wet. The exposed 

 surface is yellowish, unquestionably because of the fixation as oxide of 

 the large amount of iron which the clay contains. The deposit appears 

 to extend under the stream and outcrops on the right bank in a much 

 whiter condition, but under large boulders. Samples of the deposit were 

 carefully taken on both sides of the river and investigated in the labo- 

 ratory. The two were found to be almost identical in their general 

 characteristics. The data and results are as follows: 



Chemical analysis of the clay from the left hank. 

 [Figures give percentages.] 



Silica 

 (SiO,). 



Alu- 

 mina 

 (AI0O3) 



Fluxes. 



Loss 

 on igni- 

 tion.' 



Water 



(HjO) 

 below 

 110°. 



Tita- 

 nium 

 oxide 

 (TiO.). 



Sul- 

 phur. 



Manga- 

 nese 

 oxide 



(MnO). 



Total 

 iron 

 given 



as 

 ferric 

 oxide 

 (FejOa) 



Lime 

 (CaO). 



Mag- 

 nesia 

 (MgO). 



Soda 

 (NasO). 



Potash 



(K.0). 



39.55 

 '■42.15 



28.41 

 "30.3 



10.27 

 i'10.94 



0.35 

 '■0.37 



0.33 

 "0,36 



{By difference.) 

 0.17 



to.is 



13.62 

 'H.SO 



6.25 

 "0.00 



1.05 

 "1.12 





trace. 

 " trace. 



« Mostly water above 110*. 



^ Recalculated free from water below 110° 



