'NEW YORK ACADEMY OP SCIENCES 573 



George F. Kunz, (b) On Zirkon from near Lawton, Okla- 

 homa (by title), 

 (c) On Monazite Sand from Idaho (by 

 title). 



V. F. Marsters, The Serpentines and Associated Asbes- 

 tos of Belvidere Mountain, Vermont. 



Charles P. Berkey, Interpretation of Certain Interglacial 

 Clays and their Bearings upon Meas- 

 urement of Geologic Time. 



A. W. Grabau, Evolution of some Devonic Spirifers. 



Summary of Papers. 



Dr. Marsters stated that Belvidere Mountain lies approxi- 

 mately along the line between the counties of Orleans, Lamoille, 

 and Franklin. It is a sharp-crested ridge with a maximum 

 elevation of some 2100 feet above Eden Corners at its southern 

 termination. Three topographic elements are prominent — a 

 sharp-crested ridge forming the upper 900 feet of the mountain, 

 a cresentric plateau with a flat top 1200 feet above the valley 

 floor and rimming the end of the mountain, and lastly a steep 

 lower slope composing the foot of the plateauand extending to 

 the valley bottom. 



The upper part with steep slopes is composed of amphibolite. 

 In addition to the hornblende, which makes up seventy- five 

 per cent, of the rock, there is also present an inconsiderable 

 amount of epidote and a non-pleochroic colorless mineral 

 regarded as zoisite, together with magnetite and pyrite. Towards 

 the base, garnet becomes a prominent constituent, sufficient 

 to make a well-defined garnet zone. In nearly all cases observed 

 the garnet is largely altered to penninite, a variety of chlorite. 

 Along the garnet zone the hornblende has also undergone 

 marked alteration, in part to serpentine. The nose-like pro- 

 jection forming the plateau is composed of serpentine. In 

 this rock occur the so-called asbestos, deposits recently pros- 

 pected and worked for this product. In thin section the 

 serpentine appears to be made up largely of a felty and fibrous 

 mass, apparent only under cross nicols. It is typical fibrous 



