By These Ten Bones by Clare B. Dunkle. New York: Henry Holt, 2005.
Glaciers scoured the soil from the Highlands, often leaving behind long, narrow valleys between high ridges. This photograph, taken from the top of the Rest and Be Thankful pass, shows a typical Highland valley.
Because there is very little soil to absorb water, the water gets trapped against the rock and cannot escape. The bottom of almost every valley contains a lake, or loch, as the Scottish call it. Caught in their narrow valleys, these lochs are often long and thin.
The Highlands have a high amount of rainfall, so even the hillsides, scraped almost bare of soil, stay green. In the valleys, the ground is often marshy and waterlogged. Trapped water and decayed plants combine to form the peat bogs, which were an important source of fuel in the Highlands until very recent times. Peat bogs are not rare at all; they are everywhere.
Walking from place to place can still be difficult because the hills are so rugged and the level ground is usually boggy or underwater. Driving a carriage or wheeled cart through the Highlands was impossible before the 1800's, so the Highlanders got used to carrying loads on their backs.
Circles and standing stones are common in certain parts of the Highlands, although they are not usually as large and dramatic as the Nine Maidens that Maddie shows to Paul.
Maddie explains that the trees have given the Black Hills their name because they look black in the rain. She is describing what you see in the photo above: the pine forest looks very dark if the sun is not shining. The same phenomenon gave the Black Forest of Germany its name because it is also a forest of pine trees.
By contrast, the treeless hills look green. Purple heather blooms in the foreground of this picture.