382 Professor Edward Forbes on the Asteriadce 



present, have evidently so strong a relationship of analogy with the 

 phenomena of the past, as to warrant their safe application. 



Oro-anic remains make their first appearance in British strata 

 abundantly, and in considerable variety, about the parallel of the 

 Bala limestone, and sandstones and shales associated with it. Much 

 below that geological horizon, fossils occur, the oldest known forms 

 appearing to be LingultB, members of a genus of brachiopodous mol- 

 luscs, still represented by species which do not vary much in form 

 from their most ancient allies and predecessors. But before the de- 

 position of the Bala rocks, the evidences of life within our own area 

 are comparatively scant. In America, corresponding palaeozoic phe- 

 nomena have been described. 



The first traces of the appearance of Asteriadee, occur in rocks of 

 the Bala series, or even lower in the geological scale. They were 

 first noticed by Professor Sedgwick, who found them in beds of cor- 

 responding age in Cumberland, where they were also observed by Mr 

 Daniel Sharpe. The researches of the Geological Survey have brought 

 to light similar fossils in the Bala rocks, near Bala, and in the ashy 

 slates at Drumcannon, near Waterford, where they were found by 

 Captain James. These latter beds probably correspond in age with 

 the former. It is very remarkable that forms of star-fishes strikingly 

 similar, have been discovered in the Lower Silurian strata of the 

 United States. 



The Cumberland, Welsh, and Irish star-fishes all belong to one 

 genus. After a very careful examination of all the specimens I have 

 been able to procure (and, through the kindness of Professor Sedg- 

 wick and Mr D. Sharpe, every facility has been afforded), I am in- 

 duced to refer them to the existing genus Uraster (^Asteracanthion 

 of Muller and Troschel), members of which are at the present day 

 the most abundant star-fishes in the British seas, and throughout 

 the North Atlantic. The general aspect of the palaeozoic star-fishes 

 must have been strikingly similar to that of the Urasterice now 

 living. Indeed, impressions taken from the latter in clay would so 

 closely resemble those which we find in ancient rocks, that the cri- 

 tical eye of a naturalist would be required for the definition of their 

 specific distinctness. Nor does this arise through the obscurity or 

 imperfections of such impressions, for the external characters, so far 

 as contour and sculpture of surface, and even many points of struc- 

 ture, are very completely indicated in them, rude as they may seem. 



As yet, with the exception of the instances already referred to, 

 only one other instance of the discovery of a palaeozoic asteriad has 

 come to my knowledge, namely, that of a well-preserved species, ap- 

 parently also belonging to the genus Uraster, by M. Thorent, in the 

 " Terrains Anthraxiferes," of the department of Aisne. It is pro- 

 bable, however, that the progress of research will bring many more 

 to light. In the older secondary strata, not a few have been found, 

 both in Bi'itain and abi'oad. A doubtful form (Asterias obtusa) has 



