32 
PALEONTOLOGY OF NEW-YORX. 
The preservation of these trails in arenaceous and semi-arenaceous deposits of the Clinton 
group, in such condition that we recognize them at once, deciding without hesitation as to their 
general character and origin, suggests a question, whether similar markings, preserved under 
other circumstances, and where the primitive character of the deposit has been metamorphosed 
or obscured from other causes, may not have been differently interpreted. The fimbriated tracks 
on Plate xiii are not very different in their general character from the JYereites; and this similar¬ 
ity very forcibly impressed me on their first discovery, in the specimen fig. 2, pi. 13. If we 
compare, for example, the JYereites loomisi of Emmons ( Taconic System, in Agr. Report , Yol. 
i, pi. 15), there is not a great dissimilarity between it and the fig. 1 «, pi. 13 of this volume. 
Compare also JYereites gracilis , Emmons, Plate xvi, fig. 3, with fig. 2, pi. 13 of this volume. 
Going still farther in the figures 15, 1 c, Id, and fig. 2, and including those on Plate xiv, 
we shall be ready to conclude that these individual specimens, under other circumstances, 
might have been mistaken for species of JYereites. Again the JVtyrianites, JYemerites, &c. find 
not very dissimilar representations in the smooth trails on Plates xi and xii. It should be 
observed, also, that these specimens of trails form but an imperfect exhibition of the great 
number and variety of character which may be obtained at the localities named. 
I have not, it is true, had an opportunity of examining the specimens from which the original 
species of these genera were described by Mr. Murchison ; but those from which Professor 
Emmons has described species are, many of them, not very unlike the trails of some marine 
animal upon the surface*. It is true that in the metamorphosis which the slaty rocks of Maine 
have undergone, it may not be easy to decide that such markings have been originally trails 
upon the surface preserved by subsequent depositions. 
In comparing the actual specimens of JYereites , Myrianites , &c, from the State of Maine, 
with the specimens from the Clinton group, there is a great similarity in general character, 
though not in the material of the rock. There are also upon the Maine specimens markings 
very similar to those on Plates xi and xii of this volume, which show no evidence of fimbriae 
or other appendages like the JYereites. Many of the JYereites also have not the regular coiled 
or folded character of most cf the specimens figured, but are seen meandering over a consider¬ 
able extent of surface. Upon the same slabs, too, may be seen those of various character and 
different species crossing each other. On the one side these markings present a continuous 
groove or channel with the fimbria attached ; and on the opposite side, or portion separated, a 
continuous elevation corresponding to the groove, and neither presenting any evidence of ar¬ 
ticulations. Moreover there is not, in any of the specimens examined, any apparent remains of 
organic structure; not even a film of matter differing from the surrounding rock, or a dis¬ 
coloration of the surfacef. 
* As a fact in proof of the similarity of the trails of other animals to these supposed remains of Annelida, I may 
mention that the JVemapodia tenuissima of Emmons has been proved to be the trail of some existing animal over 
the outer surface of the rock, removing the minute lichen which covers it, and discoloring the rock heneath. 
f For further details and illustrations, see note at the end of this volume. 
