134 
LETTER XV. 
MAESTRICHT FOSSILS AMBIGUOUS APPEARANCES COMPARED 
WITH OTHER FOSSILS, FROM SWITZERLAND, ENGLAND, AND 
AMERICA. 
I HAVE, in a former letter, mentioned the fossils of St. Peter^s Moun- 
tain, and have there proposed to defer the examination of the more 
minute corals, contained in the masses belonging to that mountain. 
This I am the more inclined to do, since it would be required, in 
consequence of their similarity, to take into consideration with them, 
the gorgoni(2,jiust7'(2, and coralUnoi^ which are to be found in the Dud- 
ley limestone, and which, as well as the others, from their being so mi- 
nute as to be almost microscopic objects, would require so much time 
in their examination, and so many delicate engravings, as would have 
too much protracted the publication of this volume. This objec- 
tion, however, does not apply to the next subjects of our considera- 
tion, which are those Maastricht fossils, which are discernible by the 
naked eye. These particularly demand our attention, since their pe- 
culiar forms and structure, so different from those of other districts, 
render it exceedingly difficult to determine in what genus the greater 
part of them should be placed. This consideration, of their differing 
so widely from the fossils of other parts, is sufficient, I conceive, to 
warrant their being examined in a separate letter; and the difficulty 
of determining whether several of them should be arranged among the 
