REPORT OF THE DIRECTOR AND STATE GEOLOGIST 



few years. Fire has usually followed the ax, and old " burns 99 

 cover a considerable part of the district, often being almost im- 

 penetrable. Birch and poplar spring up to take the place of the 

 more valuable woods. 



The bare ledges of sandstone in Altona and elsewhere, known 

 locally as " Flat rocks are covered with a profusion of blue- 

 berry bushes, and the berries are picked in great quantity for 

 shipment in the summer. There is comparatively little good agri- 

 cultural land on the sheet, the greater part of the surface being 

 sandy, marshy or of bare rock. From West Chazy southward, 

 on the limestones, is the best farming land. Considerable farm- 

 ing is also done in the north of Mooers on the heavy moraine 

 there. 



Summary of geologic history 



The oldest rocks within the area of the sheet, exposed on Rand 

 hill and thence westward, are among the oldest rocks of which 

 we have knowledge anywhere on the earth's surface. Similar 

 rocks are at the surface throughout the Adirondack region, but 

 they are so old and so changed from their original condition that 

 it is an exceedingly difficult matter to decipher the history which 

 they record. They are in part of unquestionable igneous origin, 

 and have reached their present position by coming up from be- 

 low in a molten condition and then slowly solidifying. In part 

 they are believed to be old, water-deposited rocks, ancient sheets 

 of sand, mud and calcareous mud laid down on the bottom of 

 some large body of water, in all probability the sea. These are 

 now so greatly changed from their original condition that the 

 structures characteristic of rocks so formed have been almost or 

 entirely destroyed and replaced by others which are not distinc- 

 tive since they may be produced in igneous rocks as well. The 

 inference as to their original condition is based for the most 

 part on their composition. In third part they comprise rocks 

 which have the thoroughly crystalline character and foliated 

 structure of the rocks of the second group, but whose composition 

 does not suggest that they are of sedimentary origin; they may be 



