Tlie '•^ A lujen'"' -Gneiss Area. — Luqxier and Jties. 239 
two feet of the excavation, which had evidently been undisturbed, no 
fragments of flint or jasper were found, but there were numerous chips 
and irregular fragments of argillite. Mr. Volk has in a similar manner 
excavated an area of an acre or more, with corresponding results, so that 
now there seems to Ije no further reason to question the facts reported 
by Dr. Abbott. 
The evidence that this is glacial gravel, and that these argiUite im- 
plements and chips were in the gravel at its original deposition, is 
thought to be incontrovertible. The terrace here is more than a mile 
wide, and is almost perfectly level: the excavations were made running 
back from the bluflf which faces the river; the sand in which the argil- 
lite is found is stratified and compact: and there has been no chance for 
subsequent wash to cover so large an area with such a deposit, which is 
continuous with the whole terrace. Besides, ice-borne boulders, two or 
three feet in diameter, occur upon the surface at various places in the 
near vicinity. The sharply angular character of the fragments indi- 
cates that they were lost on the sjjot, and not rolled down by the flood. 
That they have not been carried down from the surface by burrowing 
animals, or through holes left by decaying taproots of trees, is clearly 
shown by the fact that only argillite is found in the lower two feet of 
the excavation. 
Prof. F. W. Putnam supplemented this paper with a statement from 
Mr. Volk, descriV)ing his subsequent work, and opened the box con- 
taining the specimens found by him, only argillite V)eing noted below 
the surface soil or tirst foot (^f depth. 
THE "AUGEN"-GNE1SS AREA, PEGMATITE VEINS 
AND DIORITE DIKES AT BEDFORD, N. Y.* 
By Lea McI. Li'vuee, Ph.D., and Heinkhh Ries, Pli.D. 
[Plates VIII and IX.] 
CONTENTS. 
Past'. Page. 
Extoat of the Area 2;» 
The "Augen"-CTneiss .". 240 
Pegmatite Veins 242 
Diorite Dilies 244 
Sfiiists 247 
Diorite Dikes 248 
Origin of the Rocks 251 
.\ppendix — The Minerals of the Peg- 
Petrography of the Area 24.") matite Veins 259 
The "Augon"-(Trneiss 245 
Extent of the Area. 
Bedford lies in the northeastern part of Westchester county, 
about forty miles north of New York city and four miles 
southeast of Bedford station on the New York <fe Harlem R. R. 
The prevailing rock in the vicinity is the gray Fordham 
gneiss, which is a tine-grained mixture of quartz, feldspar and 
biotite, showing distinct banding and normally rather quartz- 
*Read by title at the Buffalo meeting of the American Association 
for the Advancement of Science, August 25, 1896. 
