THE 



CANADIAN NATURALIST 



AND 



^uavtcvljj 3(ottvnat ot ^mxtt 



IMPRESSIONS AND FOOTPRINTS OF AQUATIC 

 ANIMALS AND IMITATIVE MARKINGS, ON 

 CARBONIFEROUS ROCKS * 



By J. W. Dawson, LL.D., F.R.S. 



The footprints and other markings of aquatic invertebrate 

 animals and of fishes, are necessarily for the most part, less 

 distinctive and importmt than those of land animals, both, 

 because less characteristic in themselves, and because reproduced 

 under similar forms in very different geological periods. The 

 former peculiarity has caused them to be neglected as of little 

 importance, or to be confounded with impressions of plants. 

 With reference to the latter, I have myself shown that the 

 impressions made by the modern King-crab faithfully represent 

 the Protlclniites, Climactichnitts, and ^«sicA;u7es of the Primor- 

 dial and Silurian, and similar comparisons have been made by 

 Salter, Jones, Dana and others, between the tracks of modern 

 Crust iceaus and worms and some of those in the oldest rocks. 



1. Protichnites, Owen. 



The footprints from the Potsdam Sandstone in Canada, for 

 which this name was proposed by Owen, and which were by him 

 referred to Crustaceans probably resembling Limulus, were 

 shown by me in 1862f to correspond precisely with those of 



* From SilUman^s Journal. f Canadian Naturalist, vol. vii. 



Vol. vii. e No. 2. 



