GEOLOGY OF THE LONG LAKE QUADRANGLE 453 



with its bordering swamps and cut-off oxbows, the broad belt of low- 

 land separating the highlands of tlie north from those of the 

 south part of the quadrangle, and the difference in character of 

 those two highland areas, the quadrangle shows a diversity of 

 topography rather unusual, even for an Adirondack map sheet. 



Practically the entire area was forest covered until recently, and 

 most of it' is 3'-et thus covered, though with a sadly changed forest. 

 The rapid growth of the village of Tupper Lake, especially as a 

 lumber center, has resulted in a steady increase in the amount 

 of cleared land in its vicinity, and within the past 15 years the 

 removal of the timber from the district has been rapid. The ordi- 

 nary wasteful lumbering of the conifers (and much of the lumbering 

 in the district has been of that type) is bad enough. But in addi- 

 tion a vast amount of small wood for paper pulp has recently 

 been cut, and also much hard wood, so that there is now a wide 

 area in the northern part of the quadrangle and thence north- 

 ward for many miles, which has been practically deforested,' and 

 through which the great forest fires of May 1904 ran widely. Here 

 as elsewhere, the Adirondack forest is disappearing, and much 

 of it disappearing in such wise that reforestation will be a difficult, 

 if not impossible matter. 



GENERAL GEOLOGY 



With the exception of the very recent, unconsolidated surface 

 deposits, all the rocks found within the limits of the quadrangle 

 are of Precambric age, or belong to the oldest known, great rock 

 group. The length of that part of the earth's history which these 

 rocks record is not known, either absolutely or relatively, but it 

 is known that the lapse of time involved is exceedingly great ^ 

 and it is quite probable that 50% or more of the entire geologic 

 history of the earth is included. Furthermore most of the Adiron- 

 dack rocks are of early Precambric age, or were formed during 

 the first half of this long time interval. They are hence to be classed 

 as among the earliest of the known rocks of the earth. 



There are at. least four great groups of these Precambric rocks, 

 and their relations to one another are, for the most part, known. 

 Unquestionably these groups are more or less capable of minor 

 subdivision, but comparatively slight progress has yet been made 

 in this direction. The study and interpretation of the history 

 which these rocks imperfectly record is a matter of extreme diffi- 

 culty, because the rocks have been profoundly modified, both 



