30 
PALEONTOLOGY OF NEW-YORK. 
PLATE XII. Fig. 4. 
This figure is from the surface of a large slab, marked by these meandering tracks. These, in 
their general aspect, are similar to those preceding ; but they present, in addition, fimbriated or 
ciliated margins, which, although not very distinct in these specimens, are nevertheless absolute 
and important features. In some portions of the same track, this character is scarcely or not at 
all visible, while in other parts they are sharp and well defined markings. 
Tracks of this character are not so abundant as the preceding kinds, but they are neverthe¬ 
less frequently found intermingled with them upon the same slab. 
Position and locality. Blackstone’s quarry, New-Hartford. 
PLATE XIII. Figs. 1 a, b, c, d; and fig. 2. 
All the figures upon this plate are of one type, though differing to some extent among them¬ 
selves. The peculiar feature of the preceding ones on Plate xi, of having a depression at each 
side, with an elevated ridge in the centre, is not here so characteristic. Most of them, indeed, 
appear to be only a single continuous fimbriated depression gradually rising from the centre 
towards the margin, where a slight ridge is formed, elevated above the surface of the surrounding 
stone. 
The central ridge which exists in some of these trails appears not to have been an original 
feature, but to have been caused by a partial filling up of the fimbriated trail. The trails of this 
character show a deeper depression along the central line than the marginal depressions in the 
other species, as if the bodies making them were heavier, or rested upon a less extent of surface. 
Fig. 1 a represents a part of the surface of a slab, marked by these fimbriated tracks. The 
trail from e to e' is clearly the oldest or first made trail, since it is crossed by the two others at 
m and p. The trail o' o was subsequently made, crossing the one e e' at p ; and again the third 
line was made from e" to e"', which crosses both the preceding ones. Between e and e", the 
meeting of the two trails is very obscure, and they appear like one continuous trail : they are 
distinct, however, though perhaps made by the same animal. 
The crossing of these trails affords a clue to the direction in which the animal moved • and 
it appears to have been from e to e', and from e" to e'". The crossing at m shows that the animal 
moved from e" to e"', since the marginal ridge of the trail crossed is pressed onward in the same 
direction. Again, in the crossing at n, the margins of the trail o o' are pushed forward in the 
direction of e'". 
The trail from e to e', first made, was probably continued beyond e'; and, after turning 
to the right beyond the margin of the specimen, comes again upon the same slab at e", re¬ 
crossing the same trail twice before leaving the slab. During this interval, another similar animal 
had crossed from o' to o. These trails throughout present no elevation in the centre. 
Fig. 1 b. A trail similar to the last, but which appears to have been partially filled by the 
flowing in of mud; 
