When the rivers are frozen communication is maintained by sledges on the Amur; but in spring and autumn the only continuous route down the Shilka and the Amur, to its mouth, is on horseback along a mountain path (very difficult across the Bureya range).
Essex and Suffolk, Suffolk and Norfolk, Cornwall and Devon, Durham and Yorkshire, Lancashire and Cheshire, are all separated by rivers, while rivers form some part of the boundaries of almost every county.
Rough weirs, formed of stakes and twigs, were erected across English rivers in Saxon times for holding up the water and catching fish, and fish-traps, with iron-wire meshes and eel baskets, are still used sometimes at weirs.
It lies in a low open valley at the confluence of the rivers Weaver and Dane, and is the centre of the principal salt-producing district in the United Kingdom.
Seven villages were partially wrecked; forests were levelled or the trees entirely denuded of bark; rivers were blocked up, and lakes were formed.
The painted box tortoise is common in the central part of the state; the snapping-turtle and the soft-shell turtle in most of the rivers and creeks; the Louisiana mud-turtle, in the coast marshes.
For about twenty years it would seem that the Yue-Chi were settled in the country between the rivers Chu and Syr-Darya, but here they were attacked again by the Hiung-nu, their old enemies, with whom was the son of the defeated Wusun chieftain.
In the rivers and lakes pike, pickerel, white fish and sturgeon supply food for the natives, and the brook trout is found in the small mountain streams. The turtle and frog also appear.
Several kinds of fish, among which are trout, salmon, grayling and white fish, inhabit many of the lakes, rivers and mountain streams, and a government fish hatchery at Bozeman, Gallatin county, restocks waters in which the supply has been diminished.
The Cetacea, however, are by no means limited to the ocean, or even to salt water, some entering large rivers for considerable distances, and others being exclusively fluviatile.