1892.] NEW YORK ACADEMY OF SCIENCES. 23 



which it surrounds, aud also an infiltration product that has 

 replaced calcite. 



Professor R. Pampelly 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. Soc. 

 Amer. II. 218, 189U,) that he walked from Fort Ann to West- 

 port and noted often in the limestones and near their lower 

 edges, fragments of the crj'stalHne 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 aud 1890, J. F. Kemp and V. F. Mars- 

 ters were in the field studying the trap dikes of the region, 

 (" TrajD dikes in the Lake Champlain Valley and the neighboring 

 Adirondacks," Tians. N. Y. Acad. Sci. XI., 13, 1891. 'The full 

 paper has been accepted as Bulletin 10 of theU. 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 183G. It proved to be a shear-zone or a crushed and 

 dynamically metamorphosed strip along a 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 

 aud 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. Tbe 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, 



