208 TRANSACTIONS OF THE [aprR. 15, 
With this analysis are placed for comparison analyses of 
anorthoclase granites from Kekequabic Lake* (II.) and Pigeon 
Pointt in Minnesota (III.). The Upham rock agrees fairly well 
in composition with that from Kekequabic Lake, being some- 
what lower in alkalies and alumina and higher in iron percent- 
age. Dr. Grant describes the latter rock as dull pink in color, 
feldspathic, with abundant augite and comparatively little quartz, 
and shows that it is an intrusive rock, exhibiting porphyritie 
facies. It would seem to be less altered than our rock, and con- 
sequently has a much larger proportion of augite; otherwise the 
resemblance is quite close. 
The results of separation with potassio-mereuric iodide solu- 
tion were as follows: 
Sp. g. 2.54—2.57 2. I, 
2.57—2.62 26. 
2.62 - 2.67 41. 
2.67—2.70 rp 
2.70—2.73 6. 
2.73—3.16 10. 
Sols 8. 
100 
The part falling between 2.62 and 2.67 was chiefly quartz and 
impure feldspar. The feldspar between 2.57 and 2.62 was 
analyzed with the following results: 
SiO,, 66.62; Al.,O3, + Fe,0,, 21.22; CaO, 0.82; 
MgO, not det. ; Na,O, 6.73 ; K,0, 2.10: 
In its outward appearance and in many details of its struc- 
ture this soda-granite is very like the “red rock” of Pigeon 
Point, in Minnesota, so fully described by W. 8S. Bayley.{ Dr. 
Bay ley determined the red rock as an anorthoclase granite with 
porphyritic phases. 
Dr. Bayley shows that the red rock is to be considered as a 
contact product resulting from the complete fusion of red sand- 
stones by an intruded gabbro. If the view held by Prof. L. W. 
Bailey as to the origin of the soda-granite be correct, there is a 
further likeness to the Pigeon Point rock, as the metamorphism 
which could produce a rock of such type must be supposed 
pushed to the point of fusion. For reasons already stated, how- 
ever, the writer is unable to take this view, and would consider 
it rather as an igneous rock of unknown relations to the felsites. 
* Minn. Geol. Survey, Ann. Rep. 1892, p. 41. 
t Amer. Jour. mark (3) XXXVII., 4. See also U.S. G. S. Bull. 109. 
{ Bull. 109, U.S. G.S. 
