30 MICHIGAN SURVEY, 1905. 



Thecla edwardsii, and the grasshoppers, Chloealtis abdominalis and conspersa, 

 Melanoplus fasciatus, amplectens and islandicus, Circotettix verruculatus, 

 and Atlanticus pachymerus. 



The Cliff. Owing to the precipitous nature of the cHff, the rock frag- 

 ments are removed as fast as they are spht off the parent rock, and the 

 environmental conditions of the chff face remain uniformly severe. The- 

 only vegetation that can exist consists of the lichens, Gyrophora (Umbilicaria) 

 vellea, Amphiloma (Pannaria) languinosum, and Biatora lucida, that manage- 

 to obtain a foothold on the face of the rock, but these are invariably de- 

 stroyed as the rock weathers away. On the ledges, however, w^here the 

 conditions are more permanent, a number of plant forms may gain a foot- 

 hold, the extent of the vegetation depending upon the age and size of the 

 ledge. On the fresher ledges the only plants are the lichens, among the 

 representative forms of which may be mentioned Stereocaulon coralloides^ 

 Parmelia conspersa and Lecidea lactea. Where a slight soil has accumulated, 

 the Harebell, Panicum xanthophysum, Polystichium loncMius, Three-toothed 

 Cinquefoil, and Goldenrods may occur. While on the larger ledges, which 

 often possess several inches of soil, the Bearberry, New Jersey Tea and 

 other forms of the heath society, together with the Juneberry, White and 

 Red Pine, Juniperus nana, Arbor Vitae and Northern Poison Oak may 

 obtain a foothold. Fig. 14. 



The fauna of the cliff face is also very limited. The ledges are too small 

 to support a characteristic fauna, but ants grasshoppers and dragon-flie& 

 are often found here. The butterfly, Grapta gracilis, was occasionally seen 

 in considerable numbers on the cliff face, but the only animal that can be 

 said to be characteristic of this habitat is the Raven which nested here. 



Station III. Substation 3. Where the cliff is broken by large ledges, 

 Fig. 15, the conditions are more stable, and the vegetation consists principally 

 of a growth of Red and White Pine -and an undergrowth of Reindeer Lichens 

 and heath plants, that extends up the cliff and across the mountain top. 

 Where these belts of pine join the mesophytic forests of the north slope 

 and river valley, the undergrowth is predominated by the Sugar and Moun- 

 tain Maples and Quaking Aspen. The fauna of these belts is peculiar. 

 Although the Pine Warbler and Crossbills are often seen here, the belt is 

 too small to support an extensive pine forest fauna, while at the same time 

 it is, perhaps, the deposit of pine needles that excludes the molluscs of the 

 mountain top and mesophytic forest. 



Talus Slope. Where the precipice is not broken by large ledges, the 

 fragments of rock that weather from its face fall to the talus slope below. 

 The finer material collects along the top of the slope, at the foot of the cliff, 

 and supports a vegetation composed of a number of species, Fig. 10. Among 

 the more prominent of these are the Thorn Apple, Red Oak, Quaking 

 Aspen, Wild Red Cherry, Round-leaved Dogwood, Juneberry, Bearberry, 

 New Jersey Tea and scattered White and Red Pine. Below this zone 

 the talus slope is strewn with dead wood and recently fallen trees, mostly 

 pines, Fig. 16. Where the cliff is composed of trap. Substation 6, the blocks 

 which fall from its face are large, and the talus slope is practically devoid 

 of vegetation with the exception of scattered patches of lichens, principally 

 Parmelia conspersa, Fig. 17. Where the cliff is composed of sandstone, 

 the talus material is finer and often supports a scattered vegetation of White 

 and Red Pine, Paper Birch, Wild Cherry Northern Poison Oak, and Virginia 

 Creeper. Toward the bottom of the slope, the first vegetation that occurs 

 are the lichens, principally Lecidea lactea and Parmelia conspersa. the latter 



