266 THE CANADIAN NATURALIST. [Vol. X. 



*' production, for those in the glacial regions differ in no respect 

 " from those nearest the Gulf of Mexico. T also lono; ao-o urged 

 '* on theorists the necessity of taking into account as a prime 

 '• factor the underground solution of limestone strata, and the 

 '' subsequent aqueous removal of the fallen debris of overlying 

 " strata, the roofings of caverns and the steeps of cliffs. 

 '• A curious illustration is offered by the peninsula of Yucatan, 

 '• on the surface of which are no streams of water, the drainage 

 *' of the whole country being underground. It is useless to 

 " repeat the o^t-told demonstration ; but it is well now that Dr. 

 '• Spencer has disembarrassed us of the chief difficulty of our 

 ^' last pre-recent water-system of the north, to remind the 

 " admirers of his great discovery that his new found ancient 

 '■ Grand river did its work not only with the constant assistance 

 "from the beginning to the end, of millions of smaller rivers, 

 " creeks, runs, rills, but also in such subordination to them as a 

 *' general acknowledges to his troops, or a contractor to his army 

 '' of navvies. . . . Our Great Lake basins although traversed 

 '• by a great river, were not excavated by it, but by a universal 

 •• vertical descent of rain-water upon the areas, lowering their 

 '• surfaces gradually and nearly equally at all points while at the 

 " same time miniuo- it throughout the whole extent of its lime- 

 '• stone underfloor; the material being removed in the ordinary 

 '• way, by rills, rivulets, and the great rivers to the sea." 



On former pages an attempt has been made to give the 

 physical configuration of the bed of Lake Ontario, and but little 

 was said about the former outlet of the basin because little is 

 absolutely known. 



Before considerina; the glacial theory of the excavation of the 

 lake, let us examine where there could have been an outlet for 

 the waters of this great river system. 



Possibilities of an outlet bi/ the St. L(twrence. The north- 

 eastern portion of Lake Ontario is very shallow. Although the 

 country surrounding it is low, yet it is underlaid by hard rocks 

 which are so frequently exposed, through the moderate thickness 

 of drift as to preclude the idea of a great buried channel existing 

 adjacent to the St. Lawrence, which a short distance below the 

 outlet of the Lake flows over Laurentian rocks. However, in 

 northern New York, but southward of the St. Ltiwrence, there are 

 some unimportant buried channels connected with the Ontario 

 basin. The St. Lawrence river itself is modern from Lake 



