Davis.] 
3T0 
[January 18 , 
are common in the flood-plains of all great rivers. The Amazon 
is made up of so many channels and lagoons that one can hardly 
name them properly 1 ; the Rhine by Carlsruhe gives several good 
examples. 
We may note here those pools that remain in the deeper parts 
of an abandoned river course ; they are of periodic occurrence in 
some of the Abyssinian branches of the Nile, where the streams 
evaporate in the dry season, driving all the river animals into the 
remaining pools. 2 In countries more permanently dried from 
their former raininess, the pools are now never strung together 
by rivers ; more frequently they disappear for a time by evapora- 
tion. 3 Examples are found in the old course of the Oxus into the 
Caspian 4 ; and along the old overflow from the Caspian to the 
Black Sea. 5 A few others are known on our northwestern 
plains. 6 The abandoned course of the Hwang Ho was for a 
time marked by a series of such pools, and a number of low 
points on the recent new course were flooded into shallow 
lakes. 7 
C. 9. Landslip Barrier Basins. Landslips often occasion an 
obstruction of drainage. Examples are found in countries shaken 
by earthquakes or in mountainous regions of heavy rainfall, and 
especially where these causes conspire, as in the Alps. 
The Calabrian earthquake already referred to produced in this 
way a lake two miles long and one broad, besides many smaller 
pools probably of the same origin. In the Cadoric Alps, Province 
Belluno, Lago di Santa Croce was formed by a land-slip about 
A. D. 600, and Lago d’Alleghe in 1771 ; a little farther north, at 
Flattach in the Mollthal, a small lake was thus made in 1854 8 
(not shown in Mayr’s Alpenkarte). In the Oisans, Western Alps, 
a slip in 1181 made a lake ten kilometers long, known as Lac de 
1 H. H. Smith, Brazil, the Amazons and the Coast, 1879, 93, 96, map. 
2 Baker, Nile Tribes of Abyssinia, 1867, 34. 
3 Humboldt called these lacs a chapelet, Asie Centrale, n, 138. 
4 Sievers, Peterm. Geog. Mitt., 1873, 288. 
5 Reclus, La Terre, i, 563. 
6 G. M. Dawson, Resources 49th Parallel, 230. 
7 N. Elias, Roy. Geogr. Soc. Journ., XL, 1870. Morrison, id. Proc., 1880. 
8 Peschel, Phys. Erdk., ii, 328. R. Hoernes says the Lago di Santa Croce is held 
by a moraine, Wien, Geol. Jahrb. xxvm, 1878, 401. 
