REPORT OF THE DIRECTOR 1916 207 



in spongy condition. Doctor Barnes cites remarks made by Sir 

 William Dawson from his observations on the formation of such 

 ice needles in the St Lawrence and elsewhere : 



The spicular ice may further grow on the bottom in the manner in which 

 crystalline needles form in some saturated saline solutions. The fact that it 

 forms most readily in open water, without any covering of ice, and in clear 

 cold weather, indicates that radiation from the bottom has an important 

 influence in its formation, but where the water is sufficiently cold it may 

 crystallize on any nucleus presented to it, and more especially, it would seem, 

 on metallic bodies and stones which are good conductors of heat. Hind 

 states that on the coast of Newfoundland anchor-ice forms in large masses 

 in the sea at depths of 60 or 70 feet, and it has been known to raise stones 

 and anchors from the bottom and to freeze round fish caught in nets. 

 These are merely desultory observations from the point of view of a 

 geologist, but they may serve to show that there are different kinds of 

 spicular ice and that they may be formed in various ways. It seems cer- 

 tain that several of these modes of formation are concerned in the produc- 

 tion of the spicular ice so troublesome in our river, so that it is not prudent 

 to limit ourselves merely to one theory of formation any farther than the 

 general principle that they all depend on the same rapid crystallization of 

 water under circumstances in which it tends to form groups of spicular 

 crystals rather than solid sheets. 



The suggestions above given can not be regarded as conclusive 

 of the ice crystal character of Fucoides, for they deal with objects 

 of different magnitudes. Professor Woodworth, in his study of 

 the Boston clay beds, has illustrated crystallizations of ice lying 

 between the laminae of the clay, such frost marks as one might 

 expect on surfaces where a small amount of moisture has been free 

 to take on crystal form under proper conditions of cold. Such 

 occurrences are frequently observed. 1 



While then the ice origin of these markings may not be conclusive 

 in itself, these suggestive similarities to ground-ice and spicular bun- 

 dles of ice crystallization, corroborated by the other evidences here 

 brought together of the work of the ice upon these ancient strands, 

 give good reason for the deduction that all these phenomena to- 

 gether are to be referred to the glacious conditions of the Portage 

 sea. 



As a corroboration of the foregoing interpretation, there is an 

 interesting reference to the grooving action of the ice foot when well 

 loaded with stones, in the account of the travels of Lyell in North 

 America on his first visit, 1841-42. This is referred to because at 



x The Glacial Brick of Rhode Island and Southeastern Massachusetts, by 

 N. S. Shaler., J. B. Woodworth and C. F. Marbut. 17th Annual Report, 

 Director U. S. Geological Survey, 1896, p. .951. 



