Editorial Comment. 51 
Warren, which laved the front of the ghieier, is believed for 
the following reasons : 
1. The beds on the north side of the hills consist of coarse 
and poorly assorted materials. 
2. The beds upon the south sides of the hills are mostly 
fine sand. 
3. The coarse beds forming the north side of the hills have 
generally a decided east-of-south dip or inclination across the 
trend of the range. 
4. The fine sands upon the south tiank of the range are hor- 
izontally bedded and are undisturbed. They must have been 
deposited in comparatively quiet water, and directly upon 
terra Jirma. 
5. The silt and sand, over 72 feet deep, constituting the 
middle ridge or heart of the South Goodman street section 
was deposited in a body of quiet water. The same is true of 
other sections, particularly in the large sand pit near Brigh- 
ton. 
6. In some exposures the fine oblique lamination of the sand 
beds indicates currents of the water southward, or east of 
south. 
7. Over the low plain southward are fine surface silts and 
workable clays, representing the ultimate product of assorting 
and deposition by water. 
8. Heavy boulders occur in the fine silts, especially south- 
west of Rochester, explainable only by flotation in ice. 
EDITORIAL COMMENT. 
The Feldspars. 
As a mineralogical assemblage the feldspars have played a 
leading role in the laboratories of all mineralogists. They 
have been the basis of the most prolonged cheniical research 
and of the most refined petrographic methods. They have 
been embraced difi'erejitly in various classifications ; the mono- 
clinic and the triclinic, the orthoclastic and the plagioclastic, 
the acid and the basic, and the last again divided into acid 
and basic. The plagioclases have latterly been arranged, ac- 
