ILLUSTRATIONS. 



ILLUSTRATIONS. 



On or opposite 



page 



Fig. 1. Geological map of a portion of the Porcupine Mountains, Michigan... 4 



2. Geological section illustrating the structure of the Porcupine Mountains. 13 



3. Portion of the Porcupine Mountains, showing location of field stations. 15 



4. General character of the rock beach, breaker line near shore 20 



5. Wave action on the Lower Beach 20 



6. Showing nature of the rock pools, crevice vegetation and lichens on the 



Middle Beach, and the stunted crevice vegetation of the Upper Beach 24 



7. General character of the rock beach, breaker line off shore 24 



8. Hemlock forest, showing dense shade and lack of undergrowth 28 



9. Deciduous forest, showing character of undergrowth 32 



10. Escarpment of' the First Range, looking west 



11. "Bald" on the top of the First Range 36 



12. The zone of stunted aspens surrounding the "bald." 36 



13. The zone of heath plants and scattered pines that surrounds the "bald" 



areas on the top of the First Range, above the aspen zone 40 



14. Face of the cliff and talus slope, looking north from Carp Lake 40 



15. Large rock ledge on the face of the cliff shown in Fig. 14 48 



16. Talus slope, showing the nature of the talus 48 



17. Upper portion of the talus slope 60 



18. General view of the Carp river valley, looking up stream and southeast 



from Station III, 5 60 



19. Carp river, showing zones of vegetation on the mud fiats 64 



20. Beaver meadow, showing grasses and sedges bordered by encroaching 



willows and alders 68 



21. Map of lower end of Isle Royale, showing the location of field stations 72 



