ECOLOGY OF ISLE ROYALE. 17 



is rocky and steep, with Birches and other trees growing down to the 

 water. The north shore has been largely burned over, and is being re- 

 placed by Birches and Small-toothed Aspens, which are now dominant; 

 the undergrowth consists of alders and the abundant Large-leaved Aster. 

 The water in the lake is brownish. At the western end there are White 

 Waterlilies, near the shore Yellow Waterlilies, Caltha pahuitris, Equis^- 

 tum, and farther back Cassandra and alders, Tamarack, Arbor Vitae, 

 and Black Spruce. 



On the north shore a rocky point projects into the water, and east of 

 this along the shore is- a floating sphagnum bog, ranging in width from 

 about 40 to 100 feet and containing Pitcher Plants, Low Cranberry, 

 Buckbean, scattered sedges and Blue Flags, and a shrub growth of 

 Cassandra, Labrador Tea and Wild Kosemary. Scattered trees of 

 Tamaracks, Arbor Vitae, and Black Spruce grow to the edge of the 

 water. Water stands in the small depressions over this bog. 



The fauna- was not studied in detail, but, the forms collected were 

 as follows: The spider, Pardosa f/laciailis, with egg masses, was found 

 running about over the wet sphagnum; a dragonfly, Aeschim, was seen 

 on wing; two species of grasshoppers were found in the wet Sphagnum; 

 Melanoplus extremus and, in the wetter places, nymphs of Mecostethus 

 lineatus were quite abundant. There were also great numbers of 

 mosquitoes and Black Flies. Upon some driftwood near the end of 

 the lake was found Physa gyrina (No. 71 A.). Yellow Perch were so 

 abundant in this lake that locally it is called Perch Lake. A Canada 

 Jay was seen in the top of a tree. 



tStation III. Western End of Bock Harbor. This station was in- 

 tended to include those localities near the western end of Rock Harbor. 



Station III, Siihstation 1 and 2. Small Island. The general character 

 of this island is shown in Fig. 15. This is a small, rocky, wooded island, 

 the trees consisting of one large White Pine, about 14 inches in diameter, 

 Arbor Vitae, Birch, Balsam, and White Spruce, the dominant ones being 

 the Balsam, Arbor Vitae and Birch, with a shrub growth of Mt. Alder, 

 Willow, Mne-bark, Mountain Ash, Amelanchier alnifoKa. Upon the rock 

 ■occurred Gladonia, Bearberry, and Low Juniper, and toward the western 

 «nd of the island, where the trees shade the ground, grew Lycopodium 

 complanatunv, mosses and Clintonia torealis. 



Of the fauna, the bird life only was examined; Cedar Birds and a 

 Song sparrow nested here, the former being quite abundant. 



The submerged western end of this island formed Station III, 2. 

 The bottom was composed of sand and angular rocks. In the shallower 

 water Anodonta grandis footiana valves were found, and live animals 

 in water about 18 inches deep. These rocks also furnished a number 

 of Limnaea stagnaUs, and a dead specimen of PlanorMs hicarinatus. A 

 few scattered rushes {Scirpus) grew at this place. 



Station III. Substation 3 and 6. Head of Bock Harlor. These 

 stations include the delta at the mouth of the largest stream flowing into 

 the Harbor, Station 3, and the sandy and rocky shallow water zone 

 extending from III, 2 around the head of the Harbor, Station 6. 



The general character of the delta. III, 3, region is shown in Fig. 16. 

 This small delta had been formed by a small sluggish brown-stained 

 brook, 15 or 20 feet wide, which enters the Harbor at this point. The 

 3 



