28 G. W. Hawes—Albany Granite, 
Tourmaline 
Schist Schist Schist Hornstone _Tourmaline 
100ft.from 50ft. from 15 ft. from 1footfrom Veinstone on 
contact. contact. contact. contact. contact. 
SiO, 61°57 63°35 30 6 
Al,Os 20°55 19°69 16°35 14°67 16°84 
Fe,03 2°02 “12, “95 2 ] 
Fe 4:28 5°48 517 3°95 5°50 
MnO 10 16 tr. 12 
CaO 24 wr. "24 30 Be 
MgO 12% ii 1°63 1°29 1°71 
Ky acl 3°47 3°40 4-08 
Na,O 1°12 bial 3°64 1:76 
TiO, 1:10 1°00 1°28 ‘93 1°02 
B,O3 Suey was tr “OF 2°96 
Fl Sasa en . tr. 
H,0. 4:09 a13 3°02 01 Loh 
100°61 100°49 100-05 101°20 100°78 
Sp. Gr 2°85 2°84 2°82 2°14 py ei 
ar 36°87 39°17 45°15 50°82 50°03 
Muscovite 49°30 44°53 : 
Biotite os ah t 43:89 {29-67 al. 
Chlorite 8°62 13°70 6°65 ae 
Titanic iron 2°09 1°90 2-43 Lit 1°94 
100-61 100-49 = 10005 = 101-20 -=——:100°78 
In these analyses a systematic and progressive series of 
obtained by others from contact schists lead to the same resu 
The kind of changes indicated by my analyses, if of less de- 
gree, are of the same kind as those that have been observed 
in the contact of granites with limestones, as for example 10 
the Harz where the limestones about the Ramberg+ have their 
CO, replaced by SiO,, forming a broad zone of lime silicates 
about the contact ; and on the contact of limestone with Mon- 
zonitt at Predazzo, where a similar lime-silicate hornstone zone 
is found to be rich in alkali directly upon the contact. 
* Die Steiger Schiefer und ihre Contactzone. Strassburg, 1877, p. 257. 
+ Lossen, Zeitschr. d. d. Geol. Gesellschaft, xxiv, p. 777. 
¢ J. Lemberg, Zeitschr. d. d. Geol. Gesellschaft, xxiv, p. 234. 
