14 FRANK D. ADAMS 
carbonic acid was expelled and the lime combined with it used in the 
production of new minerals, no further lime was fixed. In the earlier 
stages the waters given off by the granite having accomplished the 
transference of material into the limestone, passed off with the replaced 
CO, in solution, leaving the lime behind. In the later stages of the 
alteration, however, these waters, while continuing to deposit silicates 
in the limestone, made place for these latter by carrying off carbonate 
of lime in solution. 
As will be seen, the difference in chemical composition between 
Specimen 2 and Specimen 3 is very small. The more highly altered 
rock, No. 3, is rather richer in iron, magnesia, and alkalis, while it is 
considerably poorer in lime and contains less chlorine. ‘These differ- 
ences are seen to represent a slight increase in the proportion of horn- 
blende and orthoclase present and a decrease in the amount of plagio- 
clase and scapolite in the rock. 
If, for the purpose of comparing the composition of these alteration 
products with that of igneous rocks, the norms are calculated, these are 
found to be as follows. Since No. 3 is essentially the same as No. 
2, the norm of the latter rock may be taken to represent both specimens 
and with it is given the norm of the silicated portion of No. t (No. 
1 0). 
No. 2 No. 1b 
Orthoclase. 23: Ye. etc 28 7.74 
ININDIGE eS ese MA atic ae 26.20 15.24 
AMOTnthiteHs: Ge ects sere giles: 27.04 25450 
INephelimesinns jury tierleiertys IBS Olas novell weaned te Leben toe 
Sodalliters siren ay tey a eoetenaeats QnA Pra arclltaeteeea arene sari 
DIO pSicd ety wlan ies oeeets e 19.78 34.81 
Alkerimamitey saci dacmtecisyee Ne l|iny Utac eneneue cs 6.97 
Olivine? ee ine bee taal. 6.30 4.85 
Calcitenge as site senan cas eae Gr BOmr log meets 
Tila Grate Si eet cise enact eee 1.52 I.40 
Magnetite...... Bo Git 1.80 
LEAVIN IME amie a uiin aise od olaid Oo GHOA tw. |i levees 
98.90 98.40 
Wiaterai eae Ges aloreisiostnsysitelelt I.00 1.66 
99.90 100.06 
In the quantitative classification the rocks, therefore, have the 
following position: 
Eee Ca eis 
