1892. | NEW YORK ACADEMY OF SCIENCES. 23 
which it surrounds, and also an infiltration product that has 
replaced calcite. 
Professor R. Pumpelly has made one or two suggestions in 
connection with another subject that are worthy of mention. 
He states in his paper on ‘‘The Relation of secular Rock-dis- 
integration to certain transitional crystalline Schists,” (Geol. Soe. 
Amer. IT, 218, 1890,) that he walked from Fort Ann to West- 
port and noted often in the limestones and near their lower 
edges, fragments of the crystalline rocks on which they rest. 
These fragments, Pumpelly suggests, are the results of surface 
disintegration preceding the deposition of the limestone, in 
whose substance they thus became involved. 
In the summer of 1889 and 1890, J. F. Kemp and V. F. Mars- 
ters were in the field studying the trap dikes of the region, 
(‘‘ Trap dikes in the Lake Champlain Valley and the neighboring 
Adirondacks,’’ Trans. N. Y. Acad. Sci. XI., 18,1891. The full 
paper has been accepted as Bulletin 10 of the U.S. Geol. Survey). 
A large number were found, including diabase and related rocks 
and feldspar porphyries (Bostonite). They also visited a great 
reported dike at Avalanche Lake, which had been noted by 
Redfield in 1836, It proved to bea shear-zone ora crushed and 
dynamically metamorphosed strip alonga fault. (J. F. Kemp, 
“The great Shear-zone at Avalanche Lake, in the Adirondacks,” 
Amer. Jour, Sci., Aug., 1892, p. 109.) Remarks on other faults 
and shear-zones conclude the paper. 
Reference should also be made to the reports of the Tenth 
Census, in Vol. XV., on iron ores. Many details of local geology 
near the ore bodies are given. The report was issued about 
1885. Similar mention should be made of J. C. Smock’s Report 
on the Iron Mines of N. Y., 1889, Bulletin VII. of the State 
Museum. 
Valuable work on the fossiliferous rocks, although chiefly on 
the east; bank of Lake Champlain, has been done by President 
Brainerd and Professor Seely, of Middlebury, Vt., and Professor 
Whitfield, of New York. Their discoveries relate especially to the 
Calciferous and Chazy formations. Mr. C. D. Walcott, of the 
U. S. Geological Survey, has given much attention to the fringe 
of Potsdam, In Bulletin 81, of the Geol. Survey on the Corre- 
lation of the Cambrian Strata, cross-section, plate II, he has 
colored a strip on the east of the mountains as Algonkian. 
This presumably refers to the limestones and indicates for them 
an age later than the Laurentian. 
The past summer (1892) the writer was in the field and will 
later present through the N. Y. State Museum the results of 
detailed observations in Moriah and Westport townships, which, 
