188 THOMAS L. WATSON 
[x Il. la. IIa. 
SiQ pcre S oeete emcee eee 74.30 72.56 1.2383 1.2093 
ADO Fst a oheralonantrd an mccine.4 NOS ie idincomen J Pll idodte-o'b 4.0 rite. moo rer 
INGO) cildaio'c sc A000 6 806 O00 TA 72 14.81 1444 1452 
Bes @e2 elaine ieee Da Sies oll baeteiee AF. 6 i Nie eae eee oy calea IY eae ected 
1 al Ora Pe cia nircati aN ne cari trend nee criti OS Sirah ull petivecee endear lle le peer ee car 
I Bak aes eealerai inerami yetas tiers Tare Se a MS Moe aties BU et eli lo nereraee why Nations lla: aircon Hep eas 
(CRO Ga Wn cna eka tere ee chee 0.90 1.19 O16! 0212 
Ba Q iecacecueens cunccers ate erates TOTES. litres slays sha terre ane eee netitibene tlhe clrstey Susacie 
SiO Msc aioe eane eras TOME: CF "eal ah F Makes een || ee oer cae ale [Petaer ease ra 
Mig Opie cp cer tints sctharie strong trace O22 Olea al eee nee amevercraie 
Nag O aan acmieei ne ae ete: 4.61 4.94 0743 0796 
Kes OF 2 Sansui cises eee 4.52 5.30 .0481 0563 
Ei, On (lgnition) anne e nee 0.21 OOM Meas c tera lama iene nee 
PS Oli Leste racecar: TEAC a! Mae Se a dls hat erate [Bese oer 
Trotalleseprstis ese autre serene 100.05 100.55 
percentage of lime with practically no magnesia, and increased 
soda, which equals in amount the potash, indicating the pre- 
dominance of the albite molecule over that of the anorthite, and 
in case of the aplite the nearly entire absence of magnesia 
harmonizes with the absence of a ferro-magnesian accessory. 
Calculating all the lime as anorthite, all the soda as albite, and 
all the potash as orthoclase or microcline, the mineral composi- 
I. Aplite, Stone Mountain, Georgia. 
II. Stone Mountain granite inclosing aplite. 
Ta. Molecular ratios of 1. 
IIa. Molecular ratios of II. 
Watson, analyst. 
Packard, analyst. 
tion of the aplite and granite becomes: 
Potash-feldspaty jms cie ete 
Soda-feldspar.............. 
Lime-feldspar . 
Quartzh coe akennmnsnacrsiicha tiers 
ExCessrolvAllls Onur aeese tae 
Excess of Fe,O,... 
Excessroteiie OR merratnee ne 
Excess of MgO i Ane sete 2h 
ExcessiotiGa@ anne eee 
Aplite Granite. 
Sake 26.69 31.14 
38.77 41.95 
aoe 4.45 2.50 
es 28.30 21.09 
SO ie eh eiee 
ae Ay Roieeh i) lent oe ate 
EN, 85 
Leela sista ts .20 
Soke POUSas .67 
ea 21 .70 
99.81 99.10 
* Analysis #ade in the chemical laboratory of Denison University. 
2 All iron determined as ferric oxide. 
