128 The Ahierlcan GeolotjUt. August, isoi 
Befon- the sut-cossive northward outlets began to drain lake Agassiz 
below its channel of southward discharge at lakes Traverse and Big 
Stone, the border of the ice-sheet had been gradually me -d back from 
lake Winnipeg to Hudson bay, and its thick central part which occupied 
the basin of Hudson and James bays had so far disappeared as to admit 
the sea there. At a time of halt or readvance, interrupting this re- 
cession, another terminal moraine appears to have been accumulated, 
crossing the Churchill and Nelson rivers, as observed by Dr. Bell (Bul- 
letin, G. S. A., vol. i, pp. 303, 30f)). If this belonged to the time of the 
Campbell or McCauleyville beaches, as seems most probable, the extent of 
the lake during these later stages of southward outflow was even greater 
than I have supposed it to be at the time of the Herman and Norcross- 
beaches, and the area occupied by lake Agassiz in its numerous stages 
much exceeded that of my map and estimate. 
Though lake Agassiz attained vast areal extent, its duration or ex- 
tent in time was short, as is shown by the small volume of its beach de- 
posits and lacustrine sediments in comparison with lakes Bonneville and 
Lahontan and with the amount of post-glacial erosion and deposition on 
the shores of the great lakes tributary to the St. Lawrence and Nelson 
rivers. The geologic suddenness of the final melting of the ice-sheet, 
proved by the brevity of existence of its attendant glacial lakes, presents 
scarcely less difficuliy for explanation of its causes and climatic con- 
ditions, than the earlier changes from mild or warm preglacial and in- 
glacial conditions to prolonged cold and ice-accumulation. 
Somcrvillc, 3/«ss., July 7, 1S91. Warren Uimiam. 
To THE Members axd Friexds of the Correspoxdixg Geological 
Chapter of the Aggasiz Association : This brief report, covering the 
first year of the existence of the C. G. C. A. A. is published for the benefit 
of its members, and also for the information of others who are interested 
in geological pursuits and to whom the workings of the Chapter are un- 
known. 
The Chapter was organized in February. 1S90, v/ith a charter member- 
ship of sixteen. The constitution is modelled after that of the Gray 
Memorial Botanical Chapter of the A. A. It is our primary aim to or- 
ganize lovers of natural science throughout the land who are actively 
interested in geology or its kindred branches, and to establish a stated 
means of communication whereby each may know what all the others 
are doing. By this means the student or amateur geologist of New 
England comes into correspondence with the workers in the South and 
West, and acquires a more accurate knowledge of these remote regions 
than would otherwise be possible. All the machinery of the organiza- 
tion is subservient to this central idea, — the mutual encouragement and 
help of workers in difTorent sections of the country. Each member is 
expected to contribute a report every three months "giving the result 
of his studies and personal researches in geology, mineralogy, or pale- 
ontology during the previous quarter." These reports are then circu- 
lated throughout the Chapter, affording each member the opportunity 
to read, comment, and criticise. The experjence of a year is abundant 
