124 



Canadian Record of Science. 



There can be little doubt, from internal markings and 

 external form as well as from mode of occurrence, that 

 these shells were anchored by a byssus to floating timber 

 and to one another, often in great masses, just as the com- 

 mon mussel is found attached to floating logs in the 

 estuaries of modern Canadian rivers. Mr. Etheridge has 

 noticed a group from the coal-formation of Scotland, appar- 

 ently attached to a stem of a calamite, and Dr. Hind has 

 noticed the same fact. The specimen is in the collection of 

 the English Geological Survey. 



The specimens in my collections in the Peter Redpath 

 Museum, are principally from the South Joggins, where 

 myriads of these shells occur in some of the shales as thickly 

 packed together as possible. Other specimens are from 

 Pictou and from Mabou in (Jape Breton. They are con- 

 fined for the most part to the middle portion of the coal- 

 formation of which they are very characteristic, whereas 

 the shells of the next genus range in great abundance from 

 the millstone grit to the newer coal-formation inclusive. 



2. Naiadites longus, s. n. 

 4 



Fig. 4. — Naiadites 

 Joggins, enlarged, x 2. 



longus, s. n. Middle Coal-formation, S. 



Wheelton Hind, (long variety of N. carbonarius), Journal of Geolo- 

 gical Society, Vol. L, 1894, p. 440, PI. XX, Fig. 1. 



This shell, which occurs rarely in beds associated with 

 those holding the typical N. carbonarius, is regarded by Dr. 

 Wheelton Hind as a variety of the preceding. It differs 

 however, very much in form, and there do not appear to be 

 intermediate specimens, while it is rare and solitary, and 



