SAND DUNE REGION OF SAGINAW BAY. 23 



In the wooded swamps the fauna consists chiefly of the forms usually 

 found in mesophytic forests. To be mentioned are, the greater 

 abundance of the invertebrates that inhabit humus and decaying logs, 

 e. g. many gasteropods (see Baker) and. among vertebrates, the sala- 

 manders,. Amhystoma jeffersonianum antl Plethodon cincreus. Other 

 characteristic forms are the wood frog, common tree toad, whippoor- 

 will. ovenbird, redstart, and the American hare. 



We found no typical bogs within the sand region projicr, douljtless 

 because the porous soil provides too perfect drainage. That the con- 

 ditions in some of the swamps are somewhat bog-like is shown In- the 

 presence of occasional tamaracks and black spruces, but these nowhere 

 dominate the vegetation, as they do in the bogs of the clay country. 

 At Rush Lake several typical bogs occur on the east side of the inner 

 dune ridge and form islands in the lake itself. These support the 

 plants characteristic of such conditions, e. g., tamarack, black spruce, 

 Cassandra, Labrador tea, pitcher plant, etc. The fauna was not studied 

 in detail. 



Mesophytic Woods: The typical mesophytic forest of this part of 

 the state was found in the sand region proper only on low ridges of 

 considerable age, e. g., at the base of Sand Point and along the south 

 side of the inner dune ridge where it has encroached to some extent 

 upon the ridge from the clay country. On Stony and North Islands 

 the high land is clothed with mesophytic types. The conspicuous 

 plants of this formation are sugar maple, basswood, beech, ironwood, 

 butternut, shag-bark hickory, mountain maple, prickly ash and 

 spikenard with a few hemlocks and balsam firs. 



Here is found a good development of the ground fauna found in such 

 conditions. Characteristic forms are: Shield-backed locust, Plethodon 

 cinereus, myriapods, cockroaches, and many gasteropods (see Baker). 

 The other forms found here are those mentioned as characteristic of 

 the wooded swamps — ovenbird, redstart, whippoorwill, etc. 



Sedge and Grass Swamps: The swamps in which grasses and sedges 

 predominate are usually found in the swales and about the ponds. They 

 are all small, with the exception of a rather large area on the l)ase of 

 Sand Point and the wet marsh on the south end of Stony Island. (Plates 

 V, VI, VII, VIII a, XII a.) The vegetation consists of various grasses 

 and sedges, with clumps of willows, poison sumac and Roso Carolina. 

 Characteristic animals are: a number of snails (see Baker), swamp 

 tree-frog, leopard frog, ribbon and garter snakes, green snake, rattle- 

 snake, American bittern, sora rail, Virginia rail, red-winged blackbird, 

 swamp sparrow, long-billed marsh wren and yellow warbler. 



Transient Ponds: In the sand region there are a large number of 

 shallow depressions that contain water only for a part of the year. 



18554'^ 



