118 Canadian Record of Science. 



logical Society of London in 1853. 1 In this article I 

 figured four species of bivalves from the coal-formation of 

 the South Joggins, but without descriptions. Two of them, 

 one the common JSaiadites and another a narrow Anthracomi/a, 

 were referred to Modiola. Two others were referred to 

 Unio. One of these is an Anthracomya of Unio like form. 

 The other appears to be a Carbonicola, perhaps C. 

 ongulata. I remarked at the time on the vast abundance 

 of these shells and their apparently freshwater habitat. 

 This was the first publication so far as I know of these 

 fossils from the ISTova Scotia coal region. 



These shells were further referred to in the first edition 

 of " Acadian Geology" in 1855; and in the supplement to 

 that work issued in 1860, I proposed for them a new generic 

 name, Naiadites. and described them in the following terms, 

 which I quote here, as indicating conclusions which have 

 to a large extent been verified by subsequent discoveries. 



" The so-called Modiolse of the coal-measures are still un- 

 certain as to their affinities. They do not come within the 

 characters of the genera Cardinia, Anthracosia, &c, to 

 which fossils occurring in similar situations in the British 

 coal-fields have been referred. They are all thin shells, 

 marked with growth lines, but destitute of other ornamenta- 

 tion, and, so far as can be observed, without teeth. In so 

 far as external form is concerned they may all be referred 

 to the genera Modiola and Anodon. But mere form may 

 be a very fallacious guide, and I shall notice what seem to 

 me to be the distinct specific forms under the provisional 

 name Naiadites, intending thereby to express my belief that 

 they are probably allied to the UnionidaB. They are cer- 

 tainly distinct from any of the shells of the marine carboni- 

 ferous limestones, and are never associated with marine 

 fossils. It is possible that their nearest living analogue is 

 the Bysso-anodonta of D'Orbigny, from the Eiver Parana." 



At the same time five species were described, and indica- 

 tions were given as to their local and stratigraphical 

 distribution. A sixth species was subsequently discovered, 



Vol. X, p. 39. 



