74- 
resulted in a telescoping of the ordinary transitional 
stages• 
Lines of succession leading to the maple climax 
may be seen at the summit of the first range and in the 
valley of Carp River. In the first case the climax is 
reached through xerarch series, beginning with crustose 
lichens and xerophytic mosses on the exposed rock surface 
of the summit. One of the principal pioneers is Selaginella 
rupestris « which often forma a layer of humus 1-2 dm. 
thick. This together with various low-growing species, in¬ 
cluding crevice plants such as Danthonia spicata and Panicurn 
depauperatum . paves the way for the heath mat, which is 
composed largely of two species of Vaccinium (see text). A 
zone of scrubby conifers and oaks then leads gradually to the 
maple climax on the north side of the summit. 
On the south side the presence of the cliff 
forms a direct barrier to invasion from below, except where 
the escarpment has been worn down so as to produce a saddle 
aoross the range. Below the escarpment there is a talus 
slope of varying width, fringed by a mesophytic forest ex¬ 
tending below to the flood plain of Carp Hiver. In general 
this mesophytic forest is young and heterogeneous in char¬ 
acter, but it is approaching the maple climax. Its upper 
border is irregular, but forms a more or less sinuous 
