PUN ui tee eee ce rer. lyn in 48-73) 
PemOnmenites sete et gue ks 3° a 74°03 
Orthoclase and microcline.... |... 22-24 
Nepheline....... ET Se ate ae ee 2-56 
| EG) EU eae aceareers Sa OR dy cco en 4-96 
Rorniblendess ss ve 2.260 o)4 Ge hes 5:08 
BotiGen tc kad a eens ccsel es : 6-29 
Winenebites =o ee ee 1-87 ’ 
RNS THIEL. ovate eer nae ae robes, Ao al ee ate 
Shen ear. c.e  ee  rek on A 2°35 
FeMNNCTIECL ces eric LN eters GN Guin 1-34 
Water (hy.crOscOpiG)..5.2. -4. 25: 0-30 
99-68 
The calculation shows clearly the fact, ascertained 
by the study of the thin sections of the rock, that a con- 
siderable percentage of sphene is present, a mineral which 
does not occur at all in the essexite. 
The calculation also brings out clearly the fact that 
in this rock the nepheline is much more highly altered than 
in the essexite, as shown by the amount of kaolin present. 
This kaolin, however, is not entirely derived from the 
alteration of the nepheline, but appears as a haze through 
all the smaller feldspars, and hence in the extension of the 
results should be assigned in part to the nepheline and in 
part to the feldspar. 
In the Quantitative Classification the rock would have 
the following positions :— 
Class I, Persalane. 
Order 5, Canadare. 
Rang 2, Pulaskase. 
Subrang 4, Laurvikose. 
It is thus seen that the rocks from Mount Johnson 
and from Shefford mountain which, following Rosenbusch’s 
classification, have been called pulaskite, and which in the 
quantitative scheme of classification are pulaskase, are 
almost identical in composition with one another and 
with the Norwegian laurvikite, and that the nordmarkite of 
Shefford mountain is very close in composition to the 
nordmarkose of the original Scandinavian locality. 
The Transition Rock. As has been mentioned, 
there intervenes in Mount Johnson between the pulaskite 
32224—53 
