FOURTH REPORT OF THE DIRECTOR I907 73 



margin of the region, but like that was greatest on the northeast. 

 During the Beekmantown occurred an uphft which caused cessation 

 of deposition in all the region except the eastern border, confining 

 the later Beekmantown and the Chazy deposits to that district. 

 Oscillation then occurred between the Beekmantown and the Chazy, 

 pinching out the Chazy to the south. Depression then ensued on 

 the south and west, and the Lowville beds were deposited. The 

 Black River limestone followed, this being the first formation found 

 on all three sides of the region, which indicates connecting waters 

 and similar conditions on these sides. 



In the following Trenton time it seems likely that the waters 

 nearly overspread the entire present Adirondack region, though 

 shore-line conditions and small subsidence are characteristic of the 

 Mohawk valley region. 



Utica shale conditions came in from the east, and gradually en- 

 croached westward on the Trenton, so that the one thickens as the 

 other thins, the Trenton thickest on the west, the Utica on the east. 

 Following the Utica came the uplift which brought most of the 

 region above sea level. 



On Wednesday, July lo, the party regretfully bade goodbye to 

 the hospitable authorities of the Catholic Summer School, and took 

 the delightful sail dowm Lake Champlain. 



At Baldwins, the steamboat terminal at the northern end of Lake 

 George, the party were met by Prof. J. F. Kemp, by whom they 

 were guided in the Lake George valley. The first stop was Hague, 

 where the graphite bed at the Lakeside mine was studied. The 

 bed is 10 feet thick, and consists of a graphite- schist in which 

 graphite supplies the micaceous mineral. Feldspar, quartz and a 

 little pyrite constitute the associated minerals. In physical aspect 

 the beds appear but slightly changed from a shaly sandstone. The 

 floor and roof rocks are a garnet-feldspar gneiss with much silli- 

 manite. The pegmatitic phases are frequent. The several methods 

 of origin, organic ; hydrocarbons akin to petroleum ; the influence 

 of eruptive rocks, etc., were passed in review. The forms of 

 occurrence of graphite in the Adirondacks, in crystalline limestones, 

 pegmatite veins, and schists or quartzites were set forth. The in- 

 variable association even of the graphite-bearing pegmatites with 

 Grenville sediments was emphasized, and the schists seemed most 

 probably a metamorphosed carbonaceous sediment, or one which had 

 been impregnated with a heavy oil. 



