50 FOSSIL ALCYONIA. 



drophanous chalcedony, and imbedded in a matrix of car- 

 bonate of lime, which has pervaded or has supplied the 

 place of the soft spongeous part. This and the preceding; 

 fossil alcyonia are from Switzerland. 

 Alcyonium re- Alcyonium Jicus Linn, accurately depicted in the Metal- 

 sea-fig lotheca of Mercatus* as Alcyonium quintum antiquorum, 



and particularly described by Marsilli as Figue de substance 

 d'epovge Sf d'akion f , resembles much, in form, the brown 

 silicious fossil, Plate IX, fig. 4. The recent alcyonium, 

 according t© the Count, is of the form of a fig, being at- 

 tached to the rocks by branches proceeding from its smaller 

 end; its upper part being a little flattened, with a hole in 

 the middle. Its colour, he says, resembles that of tobacco, 

 and its parenchymatous substance, he thinks, cannot be 

 compared to any thing better than to nutgalls, when well 

 dried. In all these respects, a very exact agreement seems 

 to exist between the recent and fossil substances. Still, how- 

 but different, ever, the fibres running over its surface, and penetrating its 

 substance, with the grooves which appear to have been 

 formed by other fibres, which are now removed, distinguish 

 it, not only from this, but, I believe, from all known alcy- 

 Wholly silex. onia. This fossil is from Wiltshire, and appears to be formed 

 entirely of flint. 



The fossil, Plate IX, fig. 3, from Mount Randenberg, 

 near Schafhousen, in Switzerland, possesses evident marks 

 Reticular tex- of its alcyouic origin. This fossil, like those of the ramose 

 filled with kind, figured in Plate VII, has that reticular texture, which 

 chalk. appears to be peculiar to the spongy alcyonia. In this spe- 



cimen also, as well as in those, the reticular fibres are im- 

 pregnated with silica, and have their interstices tilled with 

 calcareous matter. In this, as in the fossil last described, 

 the remains of the pedicle, the organ, by which its attach- 

 ment to its appropriate spot was accomplished, are observa- 

 ble; as well as the superior opening, which passes into the 

 substance of the fossil. 

 Another simi- The fossil represented Plate IX, fig. 5, and which is from 

 lar - the neighbourhood of Saumur, being a very perfect fossil 



• Arm. 6. C. 6. p. 10 'J. t Histoire Physique de IaMcr, p. 87. 



of 



