234 Canadian Record of Science. 



an examination of the relation between the specimen and 

 the original tree. 



From the curvature of the growth rings it would appear 

 that the tree — at the time of injury — had a diameter of 

 about eighteen inches. The relationship of parts is shown 

 in figure 1 , where C represents an end view of the specimen 

 (Fig. 3 C 1 ), in relation to the growth rings of the tree : D 

 shows the intruded mass as exposed on a line of sec- 

 tion passing through the center of D 1 (Fig. 3). The slope 

 of the cleft shows the line of incision to have had the direc- 

 tion given by the line in figure 1, from which it is evident 

 that the incision was a somewhat deep one, and that our 

 specimen came from one end of it. It is also obvious that 

 this injury must have been inflicted in the winter, or at 

 least before the growth for the season began, since the in- 

 truded mass is part of the ring formed at A (Fig. 1), and 

 B, B 1 (Figs. 2 and 3). In Fig. 3, the left-hand side of the in- 

 cision represents the basal portion of the cut. Whether 

 the original cleft was filled throughout by the new growth, 

 or whether this was only partial, cannot be determined 

 from the specimen before us. 



" On Burrows and Tracks of Invertebrate Ani- 

 mals AND OTHER MARKINGS IN PALEOZOIC ROCKS." X 



By Sir J. William Dawsok, LL.D., F.R.S., F.G.S. 



This paper, which is illustrated by photographs and 

 drawings, indicates some new facts in connection with the 

 markings produced by the burrows and tracks of animals, 

 and other causes. Rusichnites and Cruziana are regarded, 

 like CUmactichnites and Protichnites, as representing probable 

 burrows or tracts of Crustaceans and Chsetopod worms, 

 Scolithus canadensis is shown to be a cylindrical burrow, 

 with accumulations of earthy castings at its mouth. The 

 relation of these burrows to the forms known as Scotolithus, 



1 From Proceedings of London Geological Society. 



