14 NEW YORK STATE MUSEUM 



development of mining and diamond drilling in the great iron ore 

 bodies at Mineville and it has been desirable to bring the records 

 up to date. There lies between the boundary of the Elizabeth- 

 town quadrangle and Lake Champlain a comparatively narrow belt 

 of country in the Port Henry quadrangle which it has seemed de- 

 sirable to treat together with the former, and as the latter includes 

 areas of Paleozoic sedimentaries the assistance of Dr Ruedemann 

 was enlisted in the solution of problems involved in the mapping 

 of these. The season's work, thus, has been largely devoted to 

 (i) reviewing and plotting new data in regard to the Mineville 

 ores, (2) verifying and amplifying observations on the Elizabeth- 

 town quadrangle, (3) traversing the Precambric formations of the 

 Port Henry sheet. In general beneath the undoubted sediments of 

 the Grenville and intimately involved with them along the borders 

 there is a great series of rocks usually gneissoid but often massive, 

 of a mineralogy ranging from the granites through the syenites to 

 and into acidic diorites which are probably of intrusive origin and 

 which represent one or more great bathyliths. Though at times 

 decidedly variable in composition this may well be due to the fusing 

 into their substance of the Grenville sediments, which range from 

 quartzites to limestones. The whole aggregate has been extensively 

 faulted. Distinct from this complex are the anorthosites and some 

 related gabbros, but between the anorthosites and the syenites there 

 are intermediate transitions which add to the difficulty of sharply 

 defined mapping. 



Valcour island, Lake Champlain. Prof. George H. Hudson is 

 finishing the survey of the eastern shore of Valcour island on the 

 scale of I :iooo and proposes to reduce the remainder of the island 

 to one of I ".3000. 



The chief reason for continuing the survey on this large scale 

 is the fact that the region is one of curiously changing dip and 

 strike. It has been influenced not only by east and west faults 

 together with some compression, but the influence of a great and 

 somewhat distributed north and south fault close to the east edge 

 of the island is very apparent. The southwesterly section has been 

 remeasured and some important corrections made, and the east 

 section of the island worked out with good exactitude. This is the 

 most important section of the island, because its beds present a 

 hundred times the area of the south section. 



An interesting result of this investigation is the recognition of 

 the repetition of the coral and stromatoporoid reefs in the Chazy 



