6 
MUSEUM BULLETIN NO. 24. 
705 feet. The difference in altitude may be due to the fact 
that the altitude as found by de Geer was a barometric deter- 
mination, which would readily account for the slight^difference. 
It is not known on what grounds Chalmers chose the higher 
altitude. 
The stratified clays underlying the sands and gravels in 
the valley leading up to Kingsmere contain fossil marine shells 
at various altitudes up to at least 510 feet. The clays are exposed 
at intervals in the bed of the creek at higher altitudes, their 
upper limit being about 605 feet, and there can be little doubt 
that they are all marine. This occurrence of stratified clays 
strongly supports the physiographic evidence as to the upper 
limit of marine submergence at this place, so that it is probable 
that, during the maximum stage of marine submergence, the 
sea stood at about 688 to 690 feet. 
At Rigaud mountain occurs the remarkable series of cobble- 
stone beaches which have been described by several geologists 
and an effort was made to determine the highest shore-line at 
that locality. The most favourable place was found to be along 
St. George road, near the central portion of the mountain, where 
boulder clay slopes occur at altitudes of from 600 to over 700 
feet. Along St. George road and about one-quarter mile west 
of the crossing of the road leading south from Rigaud village, 
a small but well formed gravel beach ridge or bar occurs, which 
appears to mark the upper limit of marine submergence at this 
locality. The crest of the gravel ridge has an altitude of 671 feet 
above sea-level, as determined by levelling from a bench-mark 
established at Rigaud station by precise levelling done by the 
Department of Public Works. Below an altitude of 600 feet 
and down to about 200 feet, at Rigaud mountain, the beaches 
are remarkably well developed and closely spaced. This is 
especially the case at altitudes from 300 to 500 feet. An excep- 
tionally strong beach also occurs at 207 feet. The remarkable 
strength of development of the beaches at this locality was due, 
doubtlessly, to the fact that, during the submergence, the mountain 
formed an island exposed on all sides to storm waves with an 
abundance of material on the slopes for the waves to handle. 
The closely spaced character of the beaches shows that an almost 
