LAURENTIAN AND EARLY PALAEOZOIC. 



31 



of these, and Nathorst has confirmed this conclusion by- 

 elaborate experiments on living animals, that these forms 

 are really trails impressed on soft 

 sediments by animals and mostly 

 by crustaceans. 



I agree with Dr. Williamson * 

 in believing that all or nearly all 

 the forms referred to Crossochorda 

 of Schimper are really animal im- 

 pressions allied to Nereites, and due 

 either to worms or, as Nathorst has 

 shown to be possible, to small crus- 

 taceans. Many impressions of this 

 kind occur in the Silurian beds of 

 the Clinton series in Canada and 

 New York, and are undoubtedly 

 mere markings. 



It is worthy of note that these 

 markings strikingly resemble the so- 

 called Eophyton, described by Torell 

 from the Primordial of Sweden, and 

 by Billings from that of Newfound- 

 land ; and which also occur abun- 

 dantly in the Primordial of New 

 Brunswick. After examining a se- 

 ries of these markings from Sweden 

 shown to me by Mr. Carruthers in 

 London, and also specimens from Newfoundland and 

 a large number in situ at St. John, I am convinced 

 that they cannot be plants, but must be markings of 

 the nature of RTiabdichnites. This conclusion is based 

 on the absence of carbonaceous matter, the intimate 

 union of the markings with the surface of the stone, 



Fig. 9. — Astropolithon 

 Hindii, an organism 

 of the Lower Cam- 

 brian of Nova Scotia, 

 possibly vegetable. 



* " Tracks from Yoredale Rocks," " Manchester Literary and Philo- 

 sophical Society," 1885. 



