320 The Ajnerican Geologist. May, )898 
transporting power of from 30 to 240 times that indicated 
by the coarser materials of the sand-plains. 
The existence of such floods is uiitcnahlc, as must also 
be the theory zvhich denunids them. Recourse to the theory 
of the existence of barriers formed by the gorging action of 
floating ice is unavailing, for the conditions during the retreat 
of the ice sheet were manifestly unfavorable to their forma- 
tion. Even the complete closing of one of the passages 
would, moreover, affect but little the conditions of the flood.* 
Conclusion. —The failure of the glacial-flood and the ice- 
banier theories to afford a satisfactory explanation of the 
phenomena in Narragansett bay brings us by the process of 
elinnnation to the alternative theory of submergence. The 
fact that the great over-wash plains on the south side of Cape 
Cod were undoubtedly of subaerial formation, has had the 
effect of causing many of the workers in this region to dis- 
regard the evidences of submergence, which are certainly 
quite manifest in places and to magnify the evidences to the 
contrary. 
The plains of the outer arm of Cape Cod were certainly 
deposited in standing water, but whether the deposition took 
place in the sea or in a body of fresh water ponded against 
the moraine,-}- is a matter of dispute. The writer believes 
strongly in the former, the low and broken character of the 
moraine — especially in that portion lying in the vicinity of 
the sand plains, where perfect continuity is most essential — 
being most unfavorable to the theory of ponding. But what- 
ever doubt there may be as to this point, there can be none 
in regard to many of the plains of Buzzards bay. The case 
here is perfectly clear and can only point to a submergence 
amounting, apparently, to at least forty feet. It was this evi- 
dence which first led me to take issue with the views of sub- 
mergence held by Davis, Woodworth and others. J That I 
*The actual decrease in discharge which would have been brought 
about by the complete closing of the Western passage would have been 
only about 1,200.000 cubic feet per second, or some 6.5 per cent. 
tA. W. Grabau, Science, n. s. vol. X, p. 334-5. 
J The views here advanced as to submergence in the regions of 
cape Cod and Buzzard's bay were first set forth in an unpublished 
essay on the "Modified Drift of Cape Cod" which received first award 
in competition for the Walker prize offered by the Boston Society of 
Natural History for 1897. 
