2 
MUSEUM BULLETIN NO. 24. 
begun after the disappearance of the ice-sheet and when sea and 
land had, approximately, attained their present relationship.) 
The marine fauna of the Champlain deposits in the St. 
Lawrence and Ottawa valleys was studied by Sir J. W. Dawson, 
J. F. Whiteaves, H. M. Ami, and other geologists, and consider- 
able information has been published regarding the character 
and distribution of the fauna, but the significance of the fauna 
with regard to the oscillations of sea-level has not been fully 
considered. 
The following is a brief summary of the results of field work 
done largely during the field season of 1915. The area in the 
vicinity of the city of Ottawa was especially studied, but numerous 
localities in’ the Ottawa valley, from Montreal 100 miles east of 
Ottawa to Renfrew 60 miles west of Ottawa, were also examined. 
Acknowledgments are due to J. Keele of this Department 
for co-operation in the field work during part of the field season, 
and to I. E. Stewart who acted as assistant. 
THE GLACIAL DEPOSITS AND DIRECTIONS OF ICE MOVEMENTS. 
The glacial deposits in the Ottawa valley consist of till or 
boulder clay and fluvioglacial sands and gravels. These deposits 
are generally concealed by a covering of marine sediments, but in 
places they appear at the surface. Where seen in sections they 
are generally found to have no great thickness. They are 
irregularly distributed and over large areas the bedrock outcrops 
with little or no drift covering. In places, also, the marine clays 
rest directly on the bedrock. In some sections the glacial 
deposits show the three-fold division, upper till, middle sands 
(fluvioglacial), and lower till. In places, the fluvioglacial sands 
appear at the surface with no till covering and outcrop as ridges 
or irregularly shaped hills. Their fluvioglacial origin is shown by 
the markedly cross-bedded character of the bedding, the coarse- 
ness of much of the material, and by the faulting and crumpling 
of the beds as if from settling following the melting of included 
ice masses. They probably have little significance as regards 
a lengthy retreat of the ice. The upper till sheet, in places, 
includes lenses or irregular masses of stratified sands and gravels 
