Annelid Tracks in the County of Clare. 283 



of the Money Point flags, and these holes, Mr Binney re- 

 gards as having resulted from the Dorsi-branchiat annelid, 

 to which he applies the name of Arenicola carbonaria, con- 

 sidering it as the ancient representative of the Arenicola pis- 

 catorum, or lug-worm of our present sandy shores. The 

 Lancashire markings do not afford the crenations which ac- 

 company the tracks on the flags of the county of Clare, and the 

 deposit in which they occur is of a somewhat different mineral 

 nature, having more of a sandy character than the equivalents 

 of the millstone grits as they are represented by the deposits 

 of Money Point and Kilkee, where the beds seem to have been 

 originally of a more muddy nature, and probably where a dif- 

 ferent habitat prevailed. 



The animals which impressed these Irish flags appears to 

 have been widely different from those which have burrowed in 

 the deposits which now form the flags of the lower portion of the 

 Lancashire coal-field, since, in these latter, neither the entrance 

 into the burrows nor the burrows themselves, equal the annelid 

 burrows of the flagstone of Clare ; the former having only 

 a diameter of £th of an inch, and being apparently round, 

 while the latter are \ an inch in breadth, and have their form 

 flattened longitudinally, which gives to them on transverse 

 section, the lenticular shape already referred to. From their 

 crenulated margins, which would indicate that the cirri were 

 more perfectly developed in the annelids to which we owe these 

 tracks, it would seem that they are more nearly allied to those 

 which have impressed the strata of the older formations, than 

 to such as have left their markings on the English carbon- 

 iferous deposits ; and if we adopt the generic appellation of Sir 

 Roderick Murchison, they might be considered as the car- 

 boniferous type of the ancient Nerites, and be designated 

 Nerites carbonarius. 



Nerites carbonarius (Harkness), Plate V. 



Tracks, when in their most perfect state, sinuous, about \ an 

 inch in breadth, and having a central line running along them, the 

 result of the ventral arch. The sides of the tracks crenulated, 

 the effect of the cirri which seem to have been largely developed. 

 Where the burrows are seen, these appear in the form of sinuous 

 hollows which have been filled up with mud, and these hollows 



