652 E. M. Kindle — Limestone Solution. 



cavities frequently pass entirely through the slab. The closely 

 placed, rounded and thin-walled cavities give to some specimens 

 a vesicular appearance. Frequently the advanced stage of 

 solution and thin walls of the cavities give the specimen a very 

 fragile character, the outer surface being composed of cell 

 walls of paper-like thinness and delicate points of limestone 

 left at the junction line of such walls after their solution. 



Fig. 1. 



Fig. 1. Limestone showing solution cavities from a depth of 150 feet, 

 Lake Ontario. 



The general appearance of these limestones which have been 

 corroded in deep water is shown in figure 1. A specimen of 

 dolomite from Lake Huron is shown in figure 2. This specimen 

 was obtained by Dr. M. Y. Williams from fishermen who took 

 it from their nets in water of considerable, but not precisely 

 determined depth. This figure is introduced because of the 

 marked contrast which it shows with the Lake Ontario 

 specimens. The well-developed cavities of corrosion in the 

 Georgian Bay specimen have a depth of about three inches, as 



