NATURAL HISTORY, TORONTO REGION
broad-leaf component is represented by poplars, and they often constitute one-fourth of the forest.
As has been shown in the article (p. 51) by Professor Coleman on the geology of the region, the city of Toronto for the most part stands on light sandy soils deposited in the Iroquois stage of Lake Ontario, and the vegetation is characteristic of such soils. The trees are mostly oaks and pines. There are, however, patches of heavier soils, and where their forest remains it is composed of beech and hem-lock, notably in Ashbridge's woods in the eastern part of the city. North of the old Iroquois beach the soil gradually becomes heavier, with an increasing clay content, and the oak-pine forest is replaced by a maple-beech forest.
On the western edge of the city, in High Park and on the Humber plains, the vegetation is distinctly Carolinian in its relationships, while on the eastern side it is Alleghanian, the city being the dividing line between the two types of flora. The transition between the two types is very abrupt in High Park, where one may pass in a few minutes from the Carolinian of the sand plains to the Alleghanian in the bottom of the deep ravines.
Toronto and vicinity offer excellent opportunities for the study of vegetation in its various habitats ; in fact there are few places where one can find on so small an area so many abrupt changes in the character of vegetation due to variations in soil and in the micro-climatic conditions. One interested in such