Lacustrine and fluviatile deposits occur intermingled with the above.
In the great lacustrine depression of Nicaragua is collected all the drainage from the eastern versant of the volcanic mountains, from the sheer western escarpment of the main cordillera, and from a large area of northern Costa Rica.
The Lacustrine period has not yet reached its close in Russia.
Those of the later Lacustrine period, on the contrary, are so numerous that there is scarcely one lacustrine basin in the regions of the Oka, the Kama, the Dnieper, not to speak of the lake-region itself, and even the White Sea coasts, where remains of Neolithic man have not been discovered.
C. Fremont and Howard Stansbury (1806-1863) furnished a general knowledge of the hydrographic features and geological lacustrine history of the Great Basin, and this knowledge was rounded out by the field work of the U.S. Geological Survey from 1879 to 1883, under the direction of Grove Karl Gilbert.