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bore a nearer resemblance, in their general characters, to some species of 
madrepores than to any of the sponges. In several of these fossils he 
discovered an outer layer, which appeared to differ from the general 
substance of the fossil; and his opinion, he thought, derived support 
from this circumstance, for, on examining the interior lamina of these 
fossils, he conceived that it much resembled the hard smooth part 
which forms the corresponding parts, in madrepores, &c. Madrepores 
and corals, he observes, are covered by a substance which has been 
distinguished as their cortical part, and immediately beneath this, 
there is a smooth substance of very close and compact texture, in 
which there are no striae nor traces of any fibres. With this latter 
substance, he thinks the external layer of these fossils exactly agrees : 
and he is confirmed in the supposition that it originally belonged to 
them, and was not derived from the matrix in which they lay, by 
observing that, in one specimen, several little flat shells of oysters 
were adhering to this surface. 
Nothing, he thinks, in the fossil kingdom approaches so near to 
these fossils, as the single-starred corals of the Baltic, described by 
Fougt, and treated of in the former part of the present volume. 
The only difference, M. Guettard remarks, is that the corals de- 
scribed by Fougt have strise which extend from the centre of the 
coral to the edge, in such a manner as to form a star. This diffe- 
rence is however sufficient to remove all idea of similarity between 
the two bodies ; since, as we have already seen, the star constitutes 
the genus Madrepora, to which those corals belong, whilst in the 
fossil bodies now under consideration, there exist none of the cha- 
racters which mark any of the species of zoophytes, which we have 
hitherto examined. 
Many of these fossil bodies, it will be seen, differ so much from 
any known recent zoophyte, that were it not that vast numbers of 
these must be concealed from us, in the numerous recesses of the 
ocean, they would be concluded to possess not the least resemblance 
