( 2 °5) 



considerable space on the eastern side above the mansion 

 and below the boulder bridge. The area west of the river 

 extends from just above this bridge down stream to a 

 point nearly opposite the old Lorillard snuff-mill, and is 

 the part commonly designated "Hemlock Grove." Its 

 total length along the river is approximately 3,000 feet; its 

 greatest width, 900 feet, is at a point on the river about 

 700 feet above the waterfall at the mansion. The total 

 area occupied by the trees on both sides of the river is be- 

 tween thirty-five and forty acres. 



While this area is mostly covered by the hemlock spruce, 

 and although they form its predominant vegetation, other 

 trees are by no means lacking; beech, ash, sweet birch, 

 red maple, hickories, oaks, dogwood, tulip-tree and other 

 trees occur, and their foliage protects the hemlocks from the 

 sun in summer to a very considerable extent; there are no 

 coniferous trees other than the hemlock, however, within 

 the forest proper. The shade is too dense for the existence 

 of much low vegetation, and this is also unable to grow at all 

 vigorously in the soil formed largely of the decaying resi- 

 nous hemlock leaves; it is only in open places left by the 

 occasional uprooting of a tree or trees by gales that we see 

 any considerable number of shrubs or herbaceous plants, 

 their seeds brought into the forest by wind or by birds. In 

 fact, the floor of the forest is characteristically devoid of 

 vegetation, a feature shown by other forests of hemlock 

 situated further north. The contrast in passing from the 

 hemlock woods to the contiguous hardwood area which 

 borders them to the west and north, toward the museum 

 building and the herbaceous grounds, is at once apparent, 

 for here we see a luxuriant growth of shrubs and of herbs, 

 including many of our most interesting wild flowers. 



21. The Gorge of the Bronx River 



The gorge of the Bronx River extends from the boulder 

 bridge at the north end of the hemlock forest southward 

 for about a mile, nearly to Pelham Avenue, and is a most 



