38 



obtained from Hudson's Bay, pretty large specimens of this coral very 

 much changed by the decomposition of their surface, either by long 

 exposure to the action of water or of air, after having lost their inha- 

 bitants, or by having been buried in the earth. The change, insuch 

 specimens as I have broken, did not, however, appear to have ex- 

 tended to such a depth as to have allowed the classing them amongst 

 the fossil corals. Boetius de Boot, gives the representation of a spe- 

 cimen evidently bearing the figure of this coral, but which from the 

 form and size, which it appears to have derived from the labours of 

 the artist, and from its having been considered by the author as 

 deserving to be ranked among the gems fit to be worn as ornaments, 

 there is good reason for believing it had undergone an impregnation 

 ( with silex*. 



Neither rnadrepora sinuosa, nor m. mceandrites appear to have been 

 described as having been seen in a mineralized state. A specimen of 

 m. areola, now before me, the history of which is unknown, bears such 

 marks as give considerable reason for believing it may with propriety 

 be considered as a fossil. Its inferior surface has evidently much suf- 

 fered from decomposition, the effects of which are still more plainly 

 observable on the superior surface, and particularly on the feather-like 

 lamellae, which have acquired an opaque whiteness, and are nearly 

 covered with a whitish-grey calcareous matter, with which the inter- 

 posed cavities are nearly filled. Although I entertain but little doubt 

 of this being a fossil coral, yet as it is not incontestibly so, I have not 

 ventured to introduce its representation. 



I do not recollect to have seen either rnadrepora abdita, m. phrygia, 

 m. dcedalea, m. cerebrum, or m. gyrosa, in a mineralized state; and am by 

 no means sufficiently acquainted with the particular forms of madre- 

 pora rcpanda, m. ambigua, m. clivosa, m. involuta, m. implicata, or of 

 m. cochlea, to be able to speak with respect to their existence as fossils. 



* Gcmmarum et Lapidum Historia. Liber II. Cap. CXLV. P. 297. 



