ILLUSTRATIONS. 



Page. 



44. Bog margin of Station V,5 16 



45. Long Island gull rookery, (V, 10) 16 



46. Pond in Tamarack — Black Spruce swamp (V, 11) 16 



47. Margin of Lily pond (V, 11) 16 



48. Black Spruce in Cassandra zone of Station (V, 11) 16 



49. Maple forest on the Desor trail (III, '04) 16 



50. Forest along Washington Brook (IV, ' 04) 16 



51. Showing origin of the glacial Great Lakes, their relation to the ice sheet 

 and their Mississippi drainage. (After Taylor and Leverett). Cham- 

 beriin and Salisbury, Geology, III, p. 396. Fig. 516 33 



52. Showing the Algonquin stage of the Great Lakes; a water barrier to north- 

 ward dispersal of the land biota. (After Taylor and Leverett). Cham- 

 berlain and Salisbury, Geology, III, p. 401. Fig. 521 34 



53. Contour Map of Isle Royale, Michigan. Contour interval 100 feet. Pre- 

 pared by Dr. A. C. Lane 34 



54. The Nipissing Great Lakes; showing the fresh-water highway or barrier 



in the west and the sea barrier in the east, (After Taylor). Chamber- 36 



liu and Salisbury, Geology, III, p. 404. Fig. 522 



55. Surface currents of Lake Superior. To show their possible influence on 



the origin of the biota. (Drawn by Hall, after Harrington.) 56 



56. "The Wendigo Road", from the clearing at the club-house to Wendigo, 

 Washington Harbor 56 



57. Long Island (V, 10), Siskowit Bay, looking toward Isle Royale Light-House. 56 



58. Gull rookery on Long Island (V, 10) 56 



59. Gull rookery on Long Island (V, 10). .' 56 



60. Eagle nest at Tobin Harbor (IV, 8) 56 



61. Variations in the shell width of Polygyra albolabris 298 



62. Variation in the shell height of Polygyra albolabris 298 



63. Lymnaea stagnalis varieties from Isle Royale 298 



