Mississippi Drainage System. — Westgate. 245 
reveals sponge spicules and several species of foraminifera. This 
island is appareutl}- a part of a moraine of the continental ice- 
sheet, the shells and foraminifera being brought from the sea 
bottom between it and the mainland. The intervening water is 
from 30 to 50 fathoms deep, but when the ice-sheet was being 
formed and plowed up its drift, the region was probably much up- 
lifted. Similar till containing shell fragments occurs also on the 
Queen Charlotte islands. 
Mr. C W. Hayks, discussing this paper, mentioned his obser- 
vations of wave-cut terraces 30 feet above the sea on islands in 
Prince William sound, opposite to Middleton island, which show 
that for a long time following the glaciation of this part of Alaska, 
the land has stood so much below its present hight. This also 
agrees with the conclusions of Dr. W. H. Dall, that mainly the 
coasts of Alaska and of Bering strait are now slowly rising. 
THE GEOGRAPHIC DEVELOPMENT OF THE EAST- 
ERN PART OF THE MISSISSIPPI DRAIN- 
AGE SYSTEM.* 
By Lewis G. Westgate, Middletown, Conn. 
CONTENTS. 
I. The Post-Carboniferous Drainage. 
1. The Post-Carboniferous Drainage. 
2. Adjustments of the Post-Carboniferous Drainage. 
(a) T!ie St. Lawrence Drainage. 
(b) The Drainage of the Cincinnati and Tennessee anti-ciinals. 
(c) T'lie Upper Mississippi. 
UD Tlie Lower Mississippi. 
IL The Cretaceous Cycle. 
1. Tlie Cretaceous Cycle. 
2. The Cretaceous Cycle in Kentucky and Tennessee. 
3. The Cretaceous Cycle in Wisconsin. 
4. The Cretaceous Cycle in Minnesota. 
5. The Cretaceous Cycle in Arkansas. 
6. Completion of the Cretaceous Cycle. 
in. The Tertiary Cycle. 
1. The Elevation of the Cretaceous Base-level. 
2. Tertiary Work in Tennessee and Kentucky. 
3. Tertiary AVork in Wisconsin. 
4. Post-Tertiary Sub-cycle. 
I. TuE Post-Carbomfkrols Drainagk. 
1. The post- Carhoutferoua drainage. The region of the Mis- 
sissippi basin has at no period been subjected to such violent dis- 
*The writer wislies to acknowledge his indebtedness to Prof. W. M. 
Davis, of ILarvard college, for help and suggestions received during the 
preparation of this paper. 
