501
North America during the postglacial period.
Different levels of temperature and precipitation
encouraged the growth of very different kinds of
plant life during this period. These diverse species released large quantities of characteristic
pollen, which was trapped within the layers of
peat preserved here. The bog was named as an
Illinois Nature Preserve in 1970 and was elevated to the status of a National Natural
Landmark in 1974.
23.2.1.7 Wetlands of Indiana State
Great Black Swamp (Fig. 23.4 ) is a glacially
caused wetland in northwest Ohio, USA, and
extends into extreme northeastern Indiana. The
Great Black Swamp is believed to be the bottom
of an ancient extension of Lake Erie. It was
named ‘Black Swamp’ for the rich, black muck
which had developed in areas where drainage
was poor. As a result, many ridges had existed
perpendicular to the direction of the fl ow to the
Plate 23.5 Kawai Nui Marsh (or Kawainui)
Fig. 23.4 Great Black Swamp (or simply Black Swamp)
23.2 Wetlands of the USA
North America during the postglacial period.
Different levels of temperature and precipitation
encouraged the growth of very different kinds of
plant life during this period. These diverse species released large quantities of characteristic
pollen, which was trapped within the layers of
peat preserved here. The bog was named as an
Illinois Nature Preserve in 1970 and was elevated to the status of a National Natural
Landmark in 1974.
23.2.1.7 Wetlands of Indiana State
Great Black Swamp (Fig. 23.4 ) is a glacially
caused wetland in northwest Ohio, USA, and
extends into extreme northeastern Indiana. The
Great Black Swamp is believed to be the bottom
of an ancient extension of Lake Erie. It was
named ‘Black Swamp’ for the rich, black muck
which had developed in areas where drainage
was poor. As a result, many ridges had existed
perpendicular to the direction of the fl ow to the
Plate 23.5 Kawai Nui Marsh (or Kawainui)
Fig. 23.4 Great Black Swamp (or simply Black Swamp)
23.2 Wetlands of the USA