20 SAND DUNE REGION OF SAGINAW BAY. 



tensive swamps that occur all along the inner dune, and the patches of 

 forest that extend out in places from the south side of the inner dune 

 ridge. 



Stony, North and Katechay Islands lie off the coast at Bayport. 

 Stony Island was worked in detail, North Island to some extent, but 

 Katechay, which is almost entirely a swamp, was not examined. Stony 

 Island consists of a rocky elevation (north end) and a series of low 

 parallel sand ridges that, with a swamp along its eastern side, forms the 

 long point on the south. This island is being built southward by the 

 formation of sand bars, and the southern end is very much like the 

 sand region on the mainland, consisting as it does of several ridges 

 with intervening swamps, but the ridges are low. The large marsh 

 on the east side is also being enclosed on the east by a sand spit, much 

 like Turtle Bay on Sand Point. North Island is also characterized 

 by a rocky nucleus and is apparently being built up to the southward, 

 as shown by the sand bar running across to Stony Island. The Charity 

 Islands could not be worked in detail in the time available, only a 

 botanical investigation being made as the basis for future work. 



General Soil Conditions. 



From the foregoing discussion it will be seen that the sand region 

 is composed of a series of roughly parallel ridges •with, intervening lakes, 

 ponds or swamps as the case maj' be. The ridges are of sand, varying 

 from the pure sand of the dunes to the mixture of sand and beach 

 gravel in the lower ridges. The swamps, ponds and lakes are also 

 apparently floored with sand, which occasionally, in the more recent 

 ones, is not covered as yet by mud or peaty deposits (e. g.. Long Lake), 

 although in the older ones (Orr Lake and Mud Pond) such deposits are 

 present. The soil of the main parts of Stony and North Islands is a 

 shallow stony loam covering the bed rock; that of the southern end 

 of Stony Island is the same as that of the sand region. 



Habitats. 



The uniformit}^ in the topography restricts the number of habitats, 

 but there are several major ones plainly indicated by the vegetation. 

 I have distinguished the following groups of environic conditions: 



Terrestrial hahitots. Aquatic habitats. 



Sand ridges. Transient ponds. 



Beach of Saginaw Bay. Permanent ponds. 



Wooded &-wamps. - Streams and artificial 

 Mesophytic woods. ditches. 



Sedge and grass swamps. Saginaw Bay. 



