46 The Ottawa Naturalist. [J>-^>^e 



dry and spongy in summer and covered mostly with sedges and 

 grasses. Sandy spots and a few low sand ridges are noticed at 

 the upper ends. Tamarack swamps, marshy and boggy places, 

 ponds and shallow lakes, are noticed in various parts of the 

 county, but these have been greatly modified and have partially 

 disappeared in recent years on account of drainage and fires. 

 Along the Lake Huron shore for nearly the whole distance from 

 Point Edward to the north-east liinit of the county are sand 

 hills and sand ridges, known also as sand dunes, usually parallel 

 with the shore, ranging from a few to nearly 100 feet in height 

 and extending back from a few rods to a mile. For a short 

 distance near Camlachie and Kettle Point, the latter place 

 famous for its peculiar rock formation, sand ridges for the most 

 part disappear and flat and naturally wet land covered with 

 the prevailing forest of the county runs down to the shore. 

 These dunes are pure sand and owe their origin exclusively to 

 local conditions and the combined action of waves and wind. 

 They are not so extensive as on the west coast of Michigan and 

 not very prominent here except at and near Port Franks, where 

 a vast amount of sand has been piled up and ridge succeeds 

 ridge for a mile back from shore. Most of them are fixed, being 

 covered with trees, shrubs and herbaceous plants that sub- 

 .stantially hold the sand in place. Near the lake, especially at 

 Port Franks, the dunes are still forming and being blown first 

 one way and then another, but nowhere, so far as observed, are 

 they encroaching upon good agricultural land. The lake shore 

 of the county running quite uniformh- north-east and south- 

 west, the question naturally arises as to why the dunes are so 

 much more prominent and massive at Port Franks than at anv 

 other point. On the west coast of Michigan it has been noticed 

 that the largest dunes have been formed at the mouths of rivers.* 

 This, perhaps, fully explains the situation at Port Franks. At 

 this point the Aux Sables River enters the lake, brings down 

 and carries into it immense amounts of sand, which is again 

 washed up by wavesjand then blown up into dunes. 



From the foregoing it will be seen that the district under 

 consideration mav be convenientlv divided into three plant 

 habitats: 1, Hydrophytic, the very wet; 2, Mesophytic. the 

 medium wet; 3, Xerophytic. the very dry. 



Hydrophytic. 

 This includes lakes, rivers, creeks, parts of their shores, 

 ponds and bogs. From the favorable situation of the locality 



*The Ecological Relations of^the^lVegetation on the"Sand Dunes of 

 Lake Michigan, hv Henrv Chandler Cowles. Botanical Gazette, Vol. 

 XXVII, Nos. 2, 3,' 4 and 5. 



