TITLES AND ABSTRACTS OF PAPERS 131 



3ire useful as a jjuido to the heilrock ireolo^y of districts wJumv actual outcrops 

 are scarce or wholly absent. 



The two dominant factors in this study — areal distribution of the bedrock 

 and direction of irlaciatiou — explain why some parts of New Hampshire are 

 t\)rtunate and others arc unfortunate in the road-nuikinj; quality of their 

 jrravt'ls and till deposits. 



Presented with tlic aid of maps and diuirrams. 

 President Merriani resumed tlic chair. 



LATK PLEJSTOCEXE CHAXGEl^ OF LEVEL I\ yORTHERX MANITOliA, CASADA ' 



HV W. A. .TOHNSTON 



[Ab.'<tr<ict) 



Tlie paper presents the results of field-work done during parts of 1917 and 

 1918. Determinations of the altitudes al)ove sealevel of the raised beaches 

 of glacial Lake Agassiz were made at numerous localities in northwestern 

 .Manitol)a, and of the marine beaches along the line of the Hudson Kay 

 Railway to supplement those already made by Messrs, J. B, Tyrrell, D. B. 

 Dowling, and William Mclnnes in this region. It is thought that the new 

 data, considered in conjunction with the well known work of Mr. Warren 

 Upham and Mr. Frank Leverett in the southern part of the Lake Agassiz 

 basin, may throw some further light upon the question of the character and 

 amount of the late Pleistocene changes of level in this part of Canada. 



The results of the work confirm, in general, Upham's view, that the south- 

 ern part of the region was uplifted earlier than the northern part and was not 

 greatly affected by the later uplift of the northern part, but indicate also 

 that the changes of level were related to two or more domes or centers of 

 uplift in different parts of the region. It was also found that the highest 

 I^ke Agassiz beach in the area north of Duck Mountain, in northwestern 

 Manito!)a. has a gradual descent toward the north, amounting to about 60 

 feet in a distance of 2.5 miles, though north and south of this area the bejich 

 has a gradual ascent toward the north. The true signiticance of this fact in 

 relation to the question of the character of the late Pleistocene change.- of 

 level has not been sMtisfMctorily determined. i>ut possible interpretations jire 

 offereil. 



Prc-^ented by title in the ahsenci' of the author, 

 (iLAciM. insToin in i in: cou wnti \ in\ i:i{ i\ the hig hem) cor'sr/n' 



II V OSCAU K. MKIN/KK 



i-'resented bv title in the absence of the author. 



•iilillslipfl by th«' ixMinissiori of rtit- I Hri-ct iriu' < Jfoloyist. (;fo|.)«icuI Sijrv<*v of Cnnnfla 



