T. S. Hunt on Lithology. 101 
A second determination of the alkalies in a portion of the 
trachyte, Ix, which had not previously been treated by acid, 
gave potash 5:40, and soda 649. A second analysis of X. gave 
potash 2-28, and soda 7-95. 
IX a. xa. mY a b. xu a, 
Silica, - - - - 1-43 cean 00 or 
Alumina, - - . i ae eS eT 1°32 484 
Peroxyd of iron, ‘- - 2-40 2:84 147 2°51 2°63 
Lime, Ss + ie, ee 1:86 414 3-50 6:49 
Magnesia, : - - ite tas 1-34 1:35 1-7 
Potash, - - - - 40 25 undet. undet. undet. 
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PHONOLITE, 
Associated with the numerous trachytic dikes at Lachine is 
one of the phonolite already referred to. It is brittle and some- 
what schistose, breaking into angular fragments, and appears to 
‘ consist of a reddish fawn-colored base, in which are disseminated 
# greenish-white rounded masses, often grouped, and apparently 
coneretionary in their structure. These greenish portions are 
Sometimes half an inch or more in diameter, and cover from one- 
» third to one-half of the surfaces. They are not very distinctly 
Seen unless the rock is moistened. The hardness of the different 
st apag does not greatly vary, and is nearly that of apatite. 
: m 
tic soda removed all of the gelatinous silica separated by the 
_ *eid, it took up only a trace of alumina; leaving a feldspathic: 
