1901 | GENETIC DEVELOPMENT OF FORESTS 311 
heath such as is shown in fig. 5, and this in turn may border on 
a small group of pines. 
As in the sand and clay series, the mesophytic forest is not 
reached until first preceded by a coniferous forest. The conif- 
erous forests on the rocks are at first very open, but ultimately 


On the faces of 
Fic. 7.—A near view of a portion of the island shown in fg. 6 
In the crevices are a number of herbaceous 
the rock are shown lichens and mosses 
arbor vitae, huckleberry, 
and woody plants; among them are goldenicld. poplar 
ninebark, Juneberry, wild red cherry, Campanula rotundifolia, and Potentilla trt- 
di i 
denaata 
the gaps are filled up, sometimes with birch and poplars, and 
thus a condition is obtained for the maple-hemlock torests. 
Some rock hills near Marquette illustrate these points. /ig. ro 
is a view from Sugar Loaf. The top of this hill is almost barren 
of vegetation. Obviously this would be the case, for the soil 
that is formed descends ‘to lower levels; in the case of steep 
