1894] PLANTS OF MONROE COUNTY. 29 



altitude of about 500 feet. The north border, traversed east and 

 west by the Rome, Watertown and Ogdensburg railroad, is about 350 

 feet above tide and 100 feet above lake Ontario. South of the area 

 lies the lofty table-land in which have been carved the valleys of 

 lakes Conesus, Hemlock, Canadice, Honeoye and Canandaigua, the 

 western members of the so-called "finger lakes". Some of the hills 

 in this high region are 2000 feet above sea-level. 



The northern part of the area is a comparatively smooth plain 

 drained directly into Lake Ontario by many small streams which, 

 near the lake, have cut into the Iroquois lake-deposits and the subja- 

 cent ice-drift. The continuity of the plain is entirely broken by the 

 recently excavated ravine of the Genesee, 200 feet deep, and by the 

 preglacial valley of Irondequoit bay. 



The eastern and southern portions of the area have a hilly 

 topography, produced by the glacier rubbing the deep subglacial 

 drift into elongated hills, parallel with the ice movement, known as 

 "drumlins"or "drumloids". In the eastern part of Monroe county 

 these drumloid ridges are very pronounced. They have a north and 

 south trend, and culminate south of Fairport in the Turk hill drumloid 

 mass. Through Henrietta and Rush, in the southern part of Monroe 

 county, the drumloids have a direction some ten to fifteen degrees 

 west of south, while along the Genesee river and in the south-west 

 part of the territory these ridges have a trend more nearly south-west. 

 In the north-west part of the area the drumloid character is merely 

 discernible in the broad, smooth swells, with a north-east by south- 

 west trend. 



List of Elevations above Ocean Level. 



lakes. Feet. 



Ontario 247 



Canandaigua.- _ 687 



Mendon Ponds 662-655 



ERIE CANAL— (WATER SURFACE). 



Between Lock 60, Macedon, and Lock 6t, Upper Macedon . . 454 



" 61 " " 62, Pittsford 461 



" 62 " " 63, Miller's 470 



" 63 " " 64, Sipple's _.. 479 



" " 64 " " 65, Reservoir _ 489 



" " 65 " " 66, first east of Rochester. 499 



Through Rochester and westward . _ 508 



