High, runs north-west past Czcnstochowa, separating the Oder from the Warta (Warthe).
- Russian Poland belongs mostly, though not entirely, to the basin of the Vistula - its western parts extending into the upper basin of the Warta, a tributary of the Oder, and its north-east spur (Suwalki) penetrating into the basin of the Memel, of which it occupies the left bank.
The Warta (450 m.) rises in the Czenstochowa hills, 900 ft.
Another canal, to the west of Leczyca, connects the Bzura, a tributary of the Vistula, with the Ner and the Warta; and the bed of the former has been altered so as to obtain regular irrigation of the meadows along its banks.
Another group of small lakes is situated in the basin of the Warta (north part of Kalisz), the largest being Goplo, 18 m.
Are not uncommon, and the rivers are generally icebound for two and a half to three months - the Warta being under ice for 70 to 80 days, the Vistula at Warsaw for 80 days and (exceptionally) even for 116, and the Memel for 100 (exceptionally for 140).
The reindeer now occurs only as a fossil; the sable, mentioned in the annals, has migrated eastwards; the wild horse, described by the annals as intermediate between the horse and the ass - probably similar to the Equus przewalskii of central Asia - is reputed to have been met with in the 13th century in the basin of the Warta, and two centuries later in the forests of Lithuania.
Westward they stretch down the Warta as far as Birnbaum (loo m.