THE EXCURSIONS. 5 



Professor Charles H. Hitchcock spoke as follows : 



■ 



I will speak only of the part of the Pleistocene excursion supervised by Profes- 

 sor J. F. Kemp, in the eastern part of the Adirondacks during the first three days 

 of the week. At Port Henry, near lake Champlaiu, we saw breccias produced by 

 the shattering of the older gneisses, adjacent to a thoroughly crystalline limestone 

 precisely like what has been known as Laurentian ; all these rocks underlying 

 the Potsdam. In a quarry farther west we were able to see this same limestone 

 traversed by a basic dike, where there were evidences of the flow of the limestone 

 around and between the fragments of the igneous intrusion. This is evidently of 

 that class of phenomena that led Emmons to say that the " primary limestone" 

 had been melted. He saw evidence of flowage and assumed it to have been the 

 result of igneous agency. At Mineville we saw one of the largest of the magnetic 

 iron ore beds, or rather two of them, roughly parallel to each other, with the asso- 

 ciated gneisses and pegmatites. We amused ourselves by breaking out zircons 

 from the debris, and were kindly entertained by Dr and Mrs Saville. 



Most of Tuesday was spent in sailing down the lake in a steam-yacht, stopping 

 particularly at Split rock, where we examined a body of titaniferous ore in gabbro. 

 The presence of the titanium renders the separation of the iron too costly to be 

 profitable. Small portions of the vein seemed to have been fused into a glass. 

 We also explored a dike of camptonite at Essex, in the Chazy limestone. 



On Wednesday we moved from Plattsburg to the Ausable forks by rail, noting 

 immense masses of sand brought down to the ancient Champlaiu ocean and de- 

 posited as a glacial delta. At Jay and Wilmington the rocks are largely gabbros 

 and norites, which exhibit signs of universal fracture or crushing. The larger 

 pieces consist of lime feldspars so placed that they have evidently been broken 

 apart, while the finer-grained matrix consists of the same mineral pulverized. 

 These veins have only been developed recently by the modern students of petrog- 

 raphy. Kemarkably smooth and polished, glaciated anorthosites were visited at 

 lower Jay. 



In order to utilize my opportunities, I left the party in Wilmington for the pur- 

 pose of studying the glaciation of the higher mountains. The results of my obser- 

 vations are not appropriate in this connection. 



Judging from my own experience I think the custom of engaging in a few days 

 of field-work before our summer meetings is a decided benefit. All our Fellows 

 would find it to their advantage to improve these opportunities as they may be 

 offered from year to year. 



For an account of the Pleistocene excursion Professor W. H. Niles way 

 called upon, and gave the following reiiort : 



REMARKS ON THE PLEISTOIENE EXCURSION 

 BY W. H. NILES 



The excursion for the study of Pleistocene geology in central- Western New York 

 was successfully made, notwithstanding the fact that Mr Frank Leverett was pre- 

 vented by illness from conducting the party over the region west of Batavia. 

 Professor H. L. Fairchild, of Rochester, conducted the party not only for the three 

 days as first planned, but very kindly continued to serve for two additional days. 



