150 The American Geologiat. Septomber, 1896 
With this warning let me conclude. The theory of descent 
has penetrated the descriptive branches of natural science 
with new ideas and set before them a nobler goal; but we 
should never forget that it remains only a theory and one that 
has to be proved. I have tried to make plain how greatly it 
is indebted for its establishment to paheontologic research; 
only I dare not conceal how many gaps are constantly brought 
to light in the very process of our argument. Science strives 
in the first place for truth. And the more clearly we keep 
ourselves conscious of the insecurity of the foundation on 
which our scientific theories rest the more actively shall we 
bestir ourselves to strengthen it by new observations and new 
facts. 
[Natural Science, ji^ay, 1895.] 
THE RETREAT OF THE ICE-SHEET IN THE 
NARRAGANSETT BAY REGION. 
By J. B. WooDWORTH, Cambridge, Mass. 
(Plate VI.) 
[Published by permission of the Director of the U. S. Geological Survey.] 
Contents. 
Introduction 150 
Retreatal deposits on the west side of the bay l.')2 
The Charlestown moraine 152 
The Slocumville stage 153 
The Wickford sub-stages 154 
The Davisville stage 154 
The Potowomut stage 155 
Greenwich Cove stage 155 
Occupasspatuxet Cove stage 157 
Passeonkquis Pond or Gaspee Point stage 157 
Pawtuxet stage 158 
Retreatal formations on the central and eastern shores of the bay 160 
Nayatt Point stage 161 
Barrington stage 161 
The esker 163 
Correlation of deposits on opposite sides of the bay 163 
Later stages of the retreat 165 
The Robin Hill stage 165 
The Fort Hill sub-stage i 165 
Central Falls stage 165 
Sand-plains between Providence and Boston 166 
The space between stages of retreat 166 
Relation of the sand-plains to sea level 167 
Introduction. 
This paper is intended to give an account of the glacial 
sand-plains, with their attendant morainal accumulations, 
which constitute the greater part of the stratified drift depos- 
