5 
Escarpment.” Eastwardly, it is first observed in Monroe County, a 
few miles west of Rochester. From thence it extends westerly 
through the whole of Orleans and Niagara Counties, constituting 
their highest elevations. In Orleans County, Oak Orchard Creek 
and its tributaries, in their descent to Lake Ontario, flow over it in 
various places. Niagara River has excavated through it its stupen- 
dous chasm. In its westerly course, as well in New York as in 
Canada, it constantly rises. At Lewiston it is 374 feet above Lake 
Ontario, and at Ancaster, near Hamilton, it reaches the height of 
510 feet. Almost from its very verge the surface of the ground, 
probably because of the dip of the subjacent rock, slopes southerly. 
North of the Mountain Ridge the surface descends rapidly, and an 
interval of comparatively level land, varying in width from one to 
fifteen miles, and lying at the average height of about 200 feet above 
Lake Ontario, is soon reached. Its level below Lake Erie is about 
141 feet. This territory, whether easterly or westerly of Niagara 
River, may be properly called the ONTARIO DiIsTRICT. 
The Catalogue presents the name of all the plants which have 
been detected within a radius of fifty miles of Buffalo, and satisfac- 
torily identified. The selection of such extended limits for a local 
catalogue was controlled by the important considerations that a 
smaller territory would not have brought within its cognizance the 
extreme southeasterly portions of the Erie District, and would have 
excluded several localities of great botanical interest, to the explora- 
tion of which especial attention has been given :—among them the 
rich and attractive region at Portage and the Falls of the Genesee. 
The altitudes of many of the places named in the Catalogue have 
been indicated upon the map which accompanies it. It is supposed 
that these will prove of no little interest. The statement that in 
respect to the growth of plants a higher elevation is equivalent to a 
higher latitude here meets with some note-worthy confirmations. 
The proposition has been more definitely embodied in the formula, 
(susceptible of easy mathematical demonstration), that, between lati- 
tudes 35 and 60, an elevation of three hundred feet is equal to one 
degree of north latitude. The higher portions of the Erie, Genesee 
and Allegany Districts, lying been the parallels of 42° 10’ and 42° 
30’ N. latitude, reach a height varying from 1500 to 2300 feet above 
the sea. The temperature, then, of these places, should be equiva- 
