24 Bulletin Wisconsin Natural History Society [Vol. 12, Nos. 1 & 2 
Many s]:)ecies of ]:)lants and animals have invaded this narrow 
strip wiiich are found nowhere else within the area studied; it is 
true, forms from the old association are left, some of which may 
]:>ersist under the changed conditions, others of which will perish. 
These species which have invaded the roadside or which have 
increased in al)undance there because of changed conditions are 
the center of interest in this association. The most characteris- 
tic plants are Anielanchier canadensis, Prurius pennsylvamca, 
Prunus virginiana, Betula papyrifera, Conjlus rostrata, Populus 
tremidoides, Populus grandidentata, and Mitchella repens; all 
deciduous plants and largely fruit-producing ones. Of the fauna 
Colaptes a. luteus, Dumetella caroUnensis, Toxostoma rufuni, and 
Tamias s. griseus are found only within this area; Bufo arneri- 
canus, Cyanocitta cristata, Melospiza meJodia, Bomhycilla cedrorum, 
Planeslicns migratorius, and Eutamias b. neglectus are here more 
al)undant than elsewhere. Chrysemys hellii tu’eeds in the sand 
along the roadside; Thamnophis sirtalis, Storeria occipitomacidata, 
and Liopeltis vernalis are in this association also. 
7. The Jlillside Association (Jig. 6). The area covered by the 
Hillside Asso(*iation belongs in reality to an ecological formation 
apart from the f)og formation, }"et it is impossible to study the 
ecological succession and the origin of the l)og fauna without 
taking into account the biota of this association. It belongs 
to the “forest on sand” formation and might well be designated the 
“Pine Association;” the general tone of the forest is pine — white, 
jack, and Norway — nowhere excessively large individuals but 
everywhere dominant in numbers. As has already been stated, the 
slo})e of this hill varies between 30° and 40°; everywhere the soil 
is sand, the humus covering seldom exceeding six inches in depth 
and often being entirely al)sent; it is well drained and dry. The 
section of the hillside studied extends in no case to the crest of the 
hill; the maximum height within the area of the Hillside Associa- 
tion is al)out fifty feet above the water level in the bog lake. 
Lycopodium ohscurum dendroideum, Chimaphila umheUata, and 
Quercus rubra are found only in the Hillside Association, though 
the last named species is rare and the small size and young age 
of tlie individuals indicate its recent advent there. Dominant 
s])e(*ies are Pinus divaricata, Pinus resinosa, Pinus strobus, Epigaea 
