WICCI.KSWOK'III: SKUI'KNTINKS oK VKUMc )N'|-. 10.") 
schists, the exphiimtinii iimst he looked lor in roiiiK-ctioii witli these 
structures. The forces which j^nxhiced these structures uiiiy have 
developed a zone of lessened pressure into which the niaKinii would 
find easy access, especially along some heddinji plane in this zone, 
if such a plane were present. If the intrusion forcing its way along 
such a plane, found the resistance less in .some places than in others, 
it would not enter as a continuous sheet, hut would select the places 
where the resistance was least. I'nder such conditions w<' might 
expect to find pipe-like intrusions along a contact plane between two 
formations. Such seems to be the case of the serpentines in Vermont. 
Comparison with othku Ahkas in I'nitko Statks and ('anaoa. 
The serpentine of Vermont does not ditt'er materially from that 
in the same belt occurring further south or in Canada. The composi- 
tion was seen on a previous page to be nearly the same in Georgia, 
Vermont, and Quebec. Mineralogically the Vermont rock lacks the 
corundum found in that from Georgia, and contains only small 
amounts of the asbestos so abundant in the Canadian region. 
In regard to alteration, the Vermont rock is more uniformly altered 
than that in the southern States, and in most cases is in a more ad- 
vanced stage. Areas of only partially altered peridotite do not exist 
here, while in the south such occurrences are numerous. In Quebec 
the stage of alteration is in some places about the same as in Vermont, 
while in others unaltered peridotite still exists. The form and size 
of the intrusions in Vermont are similar to those of the southern ones, 
but they are not as large as some of those in Canada. 
Relations of Serpentines and Steatite. 
It has been seen that steatite occurs very frequently with the ser- 
pentine, either intimately associated in the same outcrop, or in a 
similar occurrence near by. This suggests that the origin of the stea- 
tite is much the same as that of the serpentine, and that the two are 
probably very closely related. The difference in composition between 
the minerals — talc and serpentine — is merely in the amount of 
silica and water. This difference mav be due either to some slight 
