136 BOTANICAL GAZETTE [FEBRUARY 
A small portion of such a shore is shown in quadrat 8 (fig. 28). 
It was located on a small island of the outer row (Sec. 35, T. 67 
N., R. 33 W.), the same that is shown in fig. 27. The line of 
demarcation between forest and shore is here more definite than 
usual, being emphasized by the presence of a slight inward-facing 
cliff which affords some degree of protection to the area behind it. 
The shore portion of the quadrat is in a rather early stage of 
development, the only indication of future mat formation being 
the patches of the two junipers shown upon the diagram, and a 
few scattered plants of Arctostaphylos and Vaccinium pennsyl- 
vanicum in the crevices. The forested portion might have been 
taken as an excellent example of the climax type. A striking feature 
is the zone bordering the shore area thickly peopled with young 
trees, mostly balsams. This is a consequence of many windfalls, 
resulting from excessive exposure. The spruce and balsam just 
outside the quadrat on the lakeward (right) side show the tenacity 
with which trees occasionally persist under the severest conditions, 
if deeply and firmly anchored in crevices. These were low scraggy 
individuals, very small in diameter considering their age, being ' 
respectively 8.75 and 7.5 cm. thick, and 87 and 123 years old. 
c) Possible differences in the rock shore succession during the 
early history of Isle Royale 
It must not be understood that the processes which are going 
on now are necessarily exactly like those that have been in opera- 
tion during previous periods of the island’s history. Many species, 
now of considerable importance, doubtless arrived upon the island 
long after its first emergence, and without these the balance of 
power may have been very different. There is no reason, however, 
for supposing that in their essential features the successions of the 
past have differed greatly from those of the present. A suggestion 
of what the earliest vegetation may have been, at the time whet 
Isle Royale was merely a line of reefs barely above the surface of 
Lake Duluth, was obtained from a study of Gull Islands, 13 km. 
northeast of Blake Point. There appeared some surprising differ- 
ences from the normal rock shore succession as seen upon Isle 
Royale itself, and the effect of the animal life upon the flora was 
noteworthy. 
