'S04-1 257 [Dodge. 
General MEETrNO, March "21, 1804. 
Vice-President, B. .Fov JKFFRrE^^ in tlie chair. P\:)rty-one per- 
sons present. 
Prof. TI. C. Ernst read a paper on ]>ha<>ocytosis. 
THE GEOGliAPIirCAL ])EVKL()PMENT Ol*^ ALLU- 
VIAL PJVER TERRACES. 
r.Y R. E. DODGE. ^ 
Contents. 
Introduction ........ 257 
Description of a riv(M- icrriice ..... 257 
Classification of terraces ...... 25S 
Alluvial terraces and alluvial plains .... 258 
Geographical cycle and development of a nornml river 260 
Normal alluvial terraces ...... 262 
Snhnormal alluvial terraces ..... 263 
Accidental " »' 265 
Composite alluvial terraces ..... 266 
Complex or involved alluvial terraces . . . 266 
Conditions of terrace formation .... 267 
Conclusion . . . . . . , . 272 
NTRODUCTION. 
The following account of alluvial river terraces is a summary 
of tlie work I did last year in the advanced course of |)hysical 
geography at Harvard University, under the guidance of Prof. 
W. M. Davis, to whom I owe many suggestions and criticisms. 
Description of a River Terrace. 
A river terrace always consists of a plain and an accompanying 
escarpment. The terrace plain is approximately horizontal and 
usually slopes both with the grade of the stream and away from 
' Read Dpcember 6, 1893. 
PROCEEDINGS B. S. N. H. VOL. XXVI. 17 JUNE 1894. 
