618 buerows and tracks of invertebrate animals, etc. 



Discussion. 



Prof. Hfghes would like to see a combination of geologists and 

 zoologists discussing each one of the various marks. He had paid 

 most attention to Cruziana, and was glad to find that the Author 

 agreed with him that it was impossible to refer it to any surface- 

 track, and difficult to explain it on the hypothesis of its representing 

 the form of any soft-bodied animal such as Nereis. 



Dr. HiNDE observed that for many years the origin of these marks 

 had been discussed. He thought that most of them were the 

 tracks and filled-up burrows of marine organisms. The fact that no 

 carbonaceous matter had been found with these forms in the different 

 countries where they occurred was opposed to the theory of their 

 plant- origin. On the other hand, he had obtained undoubted 

 Annelid remains from some of the very beds containing the^e 

 markings. 



