Yol. 50.] ANNIVERSARY ADDRESS OF THE PRESIDENT. 67 



as deltaic ; under such conditions everything observed in the 

 palaeontology of the strata can be accounted for, whether the 

 indications be of dense vegetable growth or of vegetable drift, 

 and also whether the animal life presents a freshwater, brackish- 

 water, or marine fades. On the whole, he strongly questions the 

 merely lacustrine origin of the Coal-measures. 



On these points, again, we have the very recent testimony of 

 Dr. "Wheelton Hind, whose paper, though mainly palaaontological, 

 is eminently suggestive. In writing of the affinities of Anthraco- 

 ptera 1 and Anthracomya this author concludes to place the former 

 genus in the family Mytilidae, whilst Anthracomya is classed with 

 the Unionida3. The palaeontological details are fully worked out, 

 and present points of considerable interest. There is no evidence 

 that the shells of Anthracomya represent burrowing species, since 

 they are never found lying at right angles to the lines of stratification. 

 The shells approximate closely to Anodon, but they lack the 

 eroded obsolete beaks, the supplementary anterior-adductor muscle- 

 scar, and the equal valves of this form. 



Salter, he observes, believed that the beds in which Anthracosia, 

 Anthracoptera, and Anthracomya occur were of marine or of highly 

 brackisb-water origin. Doubtless, remarks Dr. Wheelton Hind, 

 there are truly marine beds in the Coal-measures, and these 

 contain a characteristic marine fauna, yielding Productus, Spirifer, 

 Lingula, Piscina, Aviculopecten, Posidonia, Edmondia, Sanguinolites, 

 Orthoceras, Goniatites, and Nautilus, not only towards the base as 

 in the Canister beds, but also much higher up in the series as 

 developed in North Staffordshire. In none of such beds do 

 Anthracosia, Anthracoptera, and Anthracomya occur; but, on the 

 other hand, these genera are found associated with a peculiar fauna 

 of fishes and reptiles, annelids and crustaceans, which have a close 

 affinity with recent forms inhabiting fresh water, together with a 

 flora of ferns, Sigillaria, Calamites, and Lepidodendron. The fact 

 of typical marine fossils being found in a few beds of small extent, 

 intercalated in the coal strata, seems to Dr. Hind to afford strong 

 evidence that the rest of the beds were not marine. The general 

 affinities of Anthracoptera and Anthracomya with recent freshwater 

 shells afford strong presumptive evidence of the freshwater origin of 

 the greater part of the Coal-measures, nor has any mixture of 

 fluviatile and marine forms in the same bed come to his knowledge. 



1 It seems probable that Salter's genus Anthracoptera will Lave to gire way 

 to Naiadites, Dawson. 



