266 FORESTRY IN NEW ENGLAND 



potato-growing section of Aroostook County. The underlying 

 rock is limestone, which explains its separation from the sur- 

 rounding spruce region with its rock of granite and gneiss. 



Owing to the narrowness of the northern hardwoods region 

 and to the fact that its principal species occur frequently in the 

 two bordering regions, it is extremely difficult to locate the 

 boundaries definitely in the field. Persons using the map should 

 bear this in mind, remembering that the location is only approxi- 

 mately correct. 



The topography is not rugged in nature but is usually hilly 

 and presents relatively only a small per cent of level surface. 

 In Vermont there is much steeply sloping land but in going 

 northeast across the region into Maine the topography becomes 

 much less hilly. Many of the hilltops, especially in parts of 

 Vermont, have gently rounded summits. There are few large 

 swamps in the region but small ones occasionally occur, often 

 on the tops of the hills as a result of glacial deposits, which have 

 dammed natural drainage lines. 



From its location bordering the spruce region, it follows that 

 none of New England's most important streams find their sources 

 within its boundaries, but many of them cross the region from 

 their upper sources in the other region. 



There are comparatively few slow, gently flowing streams 

 here. Most of them fall rapidly to the main rivers, but in the 

 central portion of Maine and in Aroostook County there are a 

 good many lakes and more sluggish streams. This is in the 

 leveler portion of the region, where the topography and drainage 

 conditions dift"er from the rest of the territory. 



Elevations range up to 2500 feet above sea level. There are 

 also a number of mountains of considerably higher elevation, 

 but their summits support forests typical of the spruce region 

 and should be classed as in that region. Minimum elevations 

 of about 100 feet are found in Maine, but most of the region lies 

 above 500 feet. 



A considerable area is underlaid wifh rocks of a limestone 

 nature, the marble quarries of New England being located in the 



