38 MICHIGAN SURVEY, 1908. 



been so clearly recognized as elsewhere. Thus Lane ('98, p. 187) con- 

 siders the present beach as the most distinct of any found upon the 

 island. In a way this is not surprising? when we recall the fact that 

 at former lake levels the small area of the island did not permit of 

 an extensive stream development, hence the limited quantities of sand, 

 gravel and boulders. Thus the overriding of the ice, the isolation of 

 the island in deep water, and the steep shores of resistent rocks are 

 conditions unfavorable for supplying tools with which the waves could 

 work. All of these conditions would tend to preserve the youthful 

 topographic features and exaggerate the apparent relative rate at which 

 the island emerged from the waves and the small time during which 

 the waves beat at any particular level. The materials available to the 

 present waves have therefore been cumulative. Lane ('98, pp. 188-189) 

 has recognized several evidences of a 60 foot level. 



After the formation of the Nipissing beach there was an uplift toward 

 the north, as shown by Taylor's ('97, p. 127) study of this beach on 

 the Canadian shore north of Isle Eoyale. In the vicinity of Port Arthur 

 this beach is at 60 feet; at Nipigon 90 feet, and 110 to 115 at Peninsula 

 Harbor. Such an assumed variation or tilting near Isle Eoyale sug- 

 gests the necessity of great caution in attempting to correlate the 

 various beaches and emphasizes the desirability of further field work 

 upon this subject. Lane ('98, p. 192) suggests that this northward tilt- 

 ing has tended to pond the northeastward flowing streams and to drain 

 the ones flowing in the opposite direction. Such tilting as this would 

 have considerable influence upon the biota. Even in an uplift of a few 

 feet per mile, in the case of Isle Eoyale 45 miles long, would be suflScient 

 to have a marked influence upon the swamp environment, which is one 

 of the most characteristic features of the island. In this manner a 

 swamp and its biota might migrate several miles, become a pond or 

 lake or even become drained, and other fates are suggested for ponds, 

 lakes and other environments when such a distinct trend or dynamic 

 -tendency is present in a given region. 



The change from the Nipissing to the present lake level was not a 

 sudden one, as Lane ('98, p. 191) has recognized beaches at various 

 levels showing its gradual character; the 30 and 15 foot levels are, 

 ihowever, the most distinct. A few observations were made upon two 

 of these abandoned beaches, but their height was not determined. One 

 was located just south of the mouth of Conglomerate Bay in a small 

 cove about 60 or 70 feet wide. There was an abundance of fresh drift 

 wood a few feet from the edge of the water, back of this a zone of 

 weathered and decaj^ed drift, and bej'ond this a high boulder beacli 

 containing disintegrated boulders with foliaceous lichens, while back of 

 the lichen zone came Wild Cherry, Paper Birch, Bear-berry, Wild Eose, 

 Jack Pine, Alders and Columbine. The back slope then declined into 

 a Jack Pine growth. This beach is interesting because it illustrates 

 the various stages from wave-washed, clean sand and gravel back into 

 the forest growth. Lane ('98, p. 185) refers to a lichen covered beach 

 on Sec. 10, T. 65, E. 34. The second of the beaches mentioned is located on 

 the south shore near the eastern end of Siskowdt Bay (Sec. 26, T. 65 JST., 

 E. 35 W.). The present beach is locally known as the "Greenstone 

 beach" and forms a good boat landing. 



