rlO NEW YORK STATE MUSEUM 



these syenite gneisses to be very widespread, extending far 

 beyond the limits of the anorthosites, and it is an important ques- 

 tion to determine their exact age and relations. 



At the close of the season the pre-Cambrian outcrops at Little 

 Falls and at the "Noses" in the Mohawk valley were visited to 

 form a comparison with those visited farther north. The rock 

 at Little Falls belongs to the augite syenites instead of to the 

 gabbros. It is involved with granitic and gabbroic gneisses 

 which clearly are closely related to it and of abont the same age. 

 The rock at the " Noses " is a quartzose gneiss whose relation- 

 ships are quite clearly with the crystalline limestone series, 

 though no other rocks of that series were noted. 



A visit was also made to Clinton to see Prof. Smyth's collections 

 from the western Adirondacks and for a comparison of results 

 and conclusions. As the work of the two observers had been 

 wholly independent, the harmony in conclusions which the con- 

 ference developed was most gratifjdng. 



Prof. J. F. Kemp, assisted by George I. Finlay, has continued 

 his studies of the cr^^stalline rocks north of the Mohawk valley. 

 Five weeks were spent by Mr Finlay, beginning July 3, in detailed 

 mapping of the limestone areas which occur in the town of 

 Minerva, Essex co. and in obtaining evidence as to the relation 

 between the surrounding gneisses and anorthosites. The first 

 two weeks was spent around Olmstedville. A third week was 

 spent on the limestone area along the Hudson river northward 

 from the town of North River for three miles. The remaining 

 two weeks were occupied in tracing the limestones along the 

 Boreas river for two miles north of its junction with the Hud- 

 son and in defining the similar area in the district between 

 Mink pond and the Boreas. 



A visit was also made to the Chain lakes on the line between 

 Essex county and Hamilton county, where cliffs of limestone en- 

 tirely similar in character to those in the town of Minerva are 

 exposed along the north shore. The ledges of limestone which 

 occur along the Hudson river between Blue Ledge and the month 

 of Cedar river were also mapped. The theory that the lime- 



