July 20, 1900. ] 



SCIENCE. 



m 



sediment with which we can deal in a gen- 

 eral sketch, but as already indicated it is 

 fully within the bounds of probability that 

 other kinds of rocks will be recognized to 

 possess this same character, as time goes 

 on and observations accumulate. The lime- 

 stones are in much the largest amount of 

 all the Adirondack localities in the north- 

 west, where they have been investigated by 

 Professor C. H. Smyth, Jr. St. Lawrence 

 county chiefly contains them and they are 

 also found in important areas in the neigh- 

 boring counties of Jefferson and Lewis. 

 They are not all accurately mapped as yet. 

 They constitute large northeast and south- 

 west belts as well as minor exposures, but 

 to what extent additional ones are buried 

 beneath the Potsdam, the Drift and the forest 

 growth we have no means of knowing. 

 Smyth has already mentioned four princi- 

 pal belts. The northwestern one is called 

 the Macomb. It extends from Theresa 

 township, in Jefferson county, across the 

 county line and through Rossie, Macomb 

 and De Kalb into De Peyster, St. Lawrence 

 county. This makes a distance of about 25 

 miles and the belt may be 2 miles across. 

 The next one to the southeast is the Gouv- 

 erneur belt, the largest of all. It begins in 

 Antwerp, Jefferson county, and runs for 35 

 miles through Eossie, Gouverneur, and De 

 Kalb, terminating in Canton. It varies 

 from 2 to 6 miles across but is somewhat 

 divided as regards outcrops by overlying 

 Potsdam and by gneiss. The next belt to 

 the southeast runs from Fowler township 

 through Edwards and terminates in Ens- 

 sell ; and the last of the four extends from 

 Wilna, Jefferson county, through Diana in 

 the same county, to and into Pitcairn, St. 

 Lawrence county. All lovers of minerals 

 will recognize at once in these names classic 

 localities of many species, which more than 

 any other one product have served to make 

 this region known, the world over. 

 There are other small areas in Pierrepont, 



Parishville and Potsdam further north, 

 which have been located by Professor Gush- 

 ing upon his published map of the boundary 

 of the Potsdam, executed for Professor 

 James Hall, and if we may draw inferences 

 from Professor Ebenezer Emmons' few notes 

 in the early Survey of the Second District 

 of New York, still other outcrops exist to- 

 ward the Thousand Islands of which Pro- 

 fessor Smyth will no doubt prepare descrip- 

 tions in time. But when one passes to the 

 southeast of the Diana belt, Smyth has 

 stated that for 30 miles the gneisses extend 

 without a break. Limestones are however 

 known at the Fourth lake of the Fulton 

 Chain, as recorded by Vanuxem and they 

 have been found by Smyth in small amount 

 amid gneisses near Bisby lake and on the 

 South Branch of the Moose river at its junc- 

 tion with Limekiln brook. Emmons also 

 mentions limestones as abundant around a 

 lake that he calls Lake Janet and again 

 Lake Genet, and describes as being at the 

 head of the Marion river. Lake Janet is 

 apparently the one now called Blue Moun- 

 tain lake but although fairly detailed work 

 has been done around it by my assistant D. 

 H. Newland, no record of these rocks was 

 made and there may be some mistake about 

 the earlier note. 



Despite these small areas last mentioned 

 there still remains a vast extent of crystal- 

 lines that form a broad area from northeast 

 to southwest wherein no sediments are 

 known. This is the greatest stretch of the 

 whole Adirondack region that is devoid of 

 them and as it forms a somewhat pro- 

 nounced belt, parallel to the general struc- 

 tural trend of the country, it cannot well be 

 without some special significance. Much of 

 this stretch in Franklin County has been 

 shown by Cushing to be anorthosite, but to 

 the southwest it appears to be gi'anitic 

 gneiss, of greater uniformity than is usual 

 elsewhere. 



Tlie Eastern Side. — Beginning on the north- 



