770 A. P. COLEMAN 
show first the characteristic micropegmatite of the eruptive itself, 
afterward changing into micropegmatite of a somewhat ruder kind 
in the matrix of the conglomerate. Near Moose Lake, for example, 
on the inner edge of the northern range the micropegmatitic character 
of the matrix continued for 150 paces from the edge, but had disap- 
peared in the specimen from 180 paces. The conglomerate has been 
so completely transfused and recrystallized as to be easily taken for an 
eruptive rock containing some coarser patches, and one can properly 
call the relation one of gradual transition from the eruptive to the 
conglomerate. 
CHEMICAL COMPOSITION OF THE SHEET 
From the microscopic characters of the basic and acid phases of 
the laccolithic sheet given on a former page it will be anticipated that 
the chemical composition must vary greatly. These variations were 
first demonstrated by Professor Walker in his paper on the region, 
and his analyses will be quoted here with the addition of several 
made for the Bureau of Mines. In the table given below analyses 
1 to 4 are from near the basic edge, 5 and 6 from intermediate points, 
and 7 to 10 from near the acid edge. 
Si@2) v1. 2: 49.90] 51-52| 56.89] 60.15} 64.85) 68.48) 61.93) 67.76] 68.95] 69.27 
Al203 16.32| 19.77| 19.39] 18.23] 11.44] 12.70] 13.03] 14.00] 12.74] 12.56 
INSAORE go cosas -47 30h DSi 24 41 sXO|5 o'n oes .46| 2.89 
He@ORe ce £3.54|. 102771. 7 12 -6:.04)) 16202) 0/4)-15 0) 1. S).00]| aS TO ll 15.15) aA S te 
MgO 65322) On 4G] 2 Ul e 22) ae 00 STA es O | OO mate Si7 QI 
CaO’ Bees 6n58| 8-06) 48.10) 401! 3.40 |2 heat 4 02) e= 4.) 28|) een 72 eet 
Na.O . TeS2|) 2306), 27at || te28 |) 3)02\e in72) ae sees 5) 22a yn OO les rere 
KOs aera 2215 ~7O|) I-04) 1268) 3/02)" (3°36) 2:80), 1119 3n28/) > 2805 
lelO) Goeuc 7.0 pete OO|ne The 5 355 7S) Lal3|) seOS: lsOn|) ete50 .76 
TiO2z TSA |e SO) 142 ||ertes 4 || perener 61 .84; =. 46 -43 .78 
P.O, 17 10 II a2i2 24 20 B2 19 20 06 
Mn@ ries trace | trace 30 29] trace 05 18] trace 13! trace 
IBF O)s deen o-siho panied Gila o-6.6.5llo'o.om/ orc Aisls 6 Guo aloo ages trace sleeve trace |...... 
SrOi cg ese ales lpeneeccallceraeas cA Velo sete Well eee seed ay yeasts cel ice | Bete a anaes 
INT @ Fae cece eas eal oteeteeel Waomes steer siiglanoendloaoesb|sioceg lla aod o|[p00045|o0000¢ 
COLT espe earn eo re ake ect SAL O| cpesifsceatay ee ene mene lieeesies venell aa cul oyrd [pave wean tell yeaa 
iia etre toes IS BRS olin. mice] ook xa siooososxooneullocegs clopoodcllscgo0slla00000 
Total...| 99.03] 99.71/100.53} 99.79] 98.30] 99.31| 98.76|/100.29] 99.93) 99-35 
Specific 
gravity | 3.026) 2.832] 2.834]...... 2.788) 2.673] 2.757] 2.709| 2.694] 2.724 
