2008 Edition, Dr. Paul A. Keddy
Lanark County is a microcosm of the Ottawa Valley. The following are brief summaries taken from the book. The book has more details, including a set of maps.
Geology. Lanark County has Precambrian rock in the west, as you find in the upper Ottawa Valley (including Algonquin Provincial Park) as well as limestone in the east, as you find in the lower Ottawa Valley (including the city of Ottawa). There are also extensive areas of marble. About ten thousand years ago, the western side of Lanark county was flooded by an enormous glacial lake, while the eastern side was flooded by the Champlain Sea. Hence there are extensive clay plains, of both fresh water and marine origins, which extend from Lanark County all the way to Montreal.
Human settlement. When the first Europeans arrived, the area was mainly deciduous forest, but there were also fire barrens and pine ridges, as well as lakes and beaver ponds and extensive swamps. The history is also typical: indigenous peoples were replaced by Europeans, predominantly Scottish and Irish settlers, who logged the forests and cleared for farms. On deeper soils there are now prosperous communities, while on shallow and rocky soils, farming collapsed and the forests are recovering.
Natural areas. In spite of two centuries of human settlement, there are still important natural areas left. These include deciduous forests, alvars, rock barrens, and wetlands. There are also distinctive southern species including five-lined skinks, gray rat snakes and southern flying squirrels. Shagbark hickories have crept as far north as some rocky south-facing hillsides, while a stand of hackberry trees clings to the limestone cliffs along the rapids in Carleton Place. Thirty of the most important natural areas are listed here.
So whether you live in Lanark County, or elsewhere in the Ottawa Valley, the book is a solid introduction to the natural heritage and human history of the area.
Where to Buy
You can purchase the book from stores including Mill Street Books in the historic town of Almonte, or from The Bookworm in downtown Perth. You can also buy the book at monthly meetings of the Mississippi Valley Field Naturalists.
The Christie Lake fire barrens are introduced on page 49. More detail.
The Carleton Place hackberry forest is introduced on page 59. More detail.
Reading list of scientific papers on the natural environment of the Ottawa valley