90 NINTH REPORT. 



covered deeply by glacial drift. Naturally this gives rise to marked surface 

 characteristics, diversity of topography, and soil and local climatic con- 

 ditions. 



On the other hand, the lower part of the state can be considered as a vast 

 plain of relative uniformity in general features. According to a former State 

 Geologist (Rominger, 13) the Lower Peninsula has been the center point of 

 an oceanic basin, uninterrupted marine deposits following each other in great 

 I'egularity and representing formations from the early Sihu'ian period on to 

 the end of the Coal (Carboniferous) period. The entire surface of the Lower 

 Peninsula is now covered with glacial drift, in some "places to a depth of 800 

 feet and more. The topographical outlines of toda}^ are largely the outcome 

 of the action of moving ice and flowing water, during and following the glacial 

 period, and partly due to the weathering agencies constantly at work modify- 

 ing these features. 



In its extremes the climate of the two peninsulas is somewhat excessive. 

 And yet for some not well-known reason, the edaphic and climatic conditions 

 in the upper part of the state give rise to a vegetation closely related in char- 

 acter to that prevailing in the more southern part of the state, and extremely 

 unlike that to be found around Cheboj^gan and Presc{ue Isle counties, where 

 the larger areas, at least, are covered with conifers. As in most parts of 

 eastern North America, forests constitute the most extensive and predom- 

 inating plant formation. Perhaps it is because of the influence of the abund- 

 ant rainfall, and the very frequent heavy fogs along the lake shore through- 

 out the year — conditions most favorable to tree growth — that Upper Mich- 

 igan presents the aspect of so richly wooded a country. 



FLORA AND DISTRIBUTION. 



The flora of the Marc^uette Quadrangle naturally falls intotliree groups — 

 that composing the vegetation of rocks and ridges, and that found on sandy 

 soils and in swamj^y places. By way of introducing some order into the 

 variety of ways in which these groups may be treated, they will, be taken up 

 in conformity to the line of survey, under the following heads : 



Beach and Promontory. — Beginning at Presciue Isle, the ];each at the 

 point studied consists of outcropping strata of Potsdam sandstone, tilted 

 about 20°, and farther north of an exposed trap-dike and promontory. Con- 

 tinualh^ exposed to the action of waves during the larger part of the year, 

 and to the action of ice during the latter part of winter, even considerately 

 above the water line the rocks are bare, furnishing neither soil nor a foothold 

 for plants. But beyond the limit reached by waves and ice life can exist. 

 The lichen formation precedes all others, consisting largely of Parmelia con- 

 spersa, Lecidea lactea, Stereocaulon coralloides; a few xerophytic mosses 

 gain a foothold, soon forming a slight soil, and evidently representing a brief 

 stage in a succession, which will support still higher forms. In crevices, 

 disintegration permits an accumulation of soil. Several of the hardier plants* 

 like Sibbaldiopsis tridenta, Campanula rotundifolia, Agrostis h3'emale, 

 Sohdago uliginosa, S. hispida, Opulaster oiDulifolius, and Bettula papj^rifera, 

 are to be found here, and in protected places, even more shade-requiring 

 forms occur, such as Phegopteris dryopteris, Onoclea sensibilis ancl Dry- 

 opteris noveboracensis. Pools, formed by large fissures and by the disin- 

 tegration of large portions of rock, are quite numerous. The vegetation 



* For a more complete list see "Distribution of characteristic plants in the Marquette 

 Region," pp. 98-103. 



