MEDINA SANDSTONE. 
47 
The Fucoides Harlani is everywhere typical of the Medina sandstone, continuing through¬ 
out its whole extent so far as known. It occurs in the Third district, at Fulton, Oswego 
county, and in the Fourth district in Wayne county, at Rochester, Medina, and on the Nia¬ 
gara river. In Canada, it is found along the Welland canal, besides numerous intermediate 
places. According to Mr. Vanuxem, it occurs in Pennsylvania and Virginia, having the same 
association. It thus becomes the most characteristic indication of the rock, and is considered 
as one of its essential organic forms, occurring in no other rock, and being an example of a 
peculiar type which commenced and terminated its existence with this rock. The second 
figure in the woodcut represents that part of the fossil near the base, from which the branches 
diverge. Fig. 1 is a more common form, and the most abundant is that of single, elongated, 
straight or curved branches, crossing each other in various directions upon the surface of the 
stone. Their annular ridges or apparent articulations are always visible, except when much 
weathered, and from these it was formerly supposed to be the stem of a crinoid. The sub¬ 
stance of this fossil is frequently replaced by pebbles and small angular fragments, and in such 
cases the beautiful annulated structure is less distinctly visible. The Fucoides auriformis 
(PI. I. fig. 2) is equally common in the Fourth district, it being abundant at Rochester, Medina, 
and other places, holding the same position as the first. It appears slightly elevated above 
the surface of the stone in the form represented in the figure, like a collection of small auri¬ 
form appendages, whence it receives its name. 
The Fucoides heterophyllus (PI. I. fig. 3) is allied to the preceding, and abounds at 
Rochester. This figure will be readily recognized by any one who has explored the river 
banks below the lower falls. The representation is of its more common form, but there are 
many other varieties which may be referred to this species. Its great uniformity in general 
appearance and manner of occurrence, indicates that it is organic ; and for the present all 
forms of marine vegetation, which have no characters sufficiently marked to place them in 
other families, are referred provisionally to the Fucoides.* Some other forms appear in the 
rock, apparently referable to marine vegetation. 
Throughout all the red portions of the rock, no animal remains have been found, with the 
exception of fragments of Lingula. Whether the deposition of mud charged with ferruginous 
matter was unfavorable to their existence, or whether subsequent causes have obliterated their 
remains, it is perhaps not easy to decide. In the Old Red Sandstone, which is equally charged 
with the oxide of iron, and often very highly colored, the remains of fishes are perfectly pre¬ 
served ; the scales and fins, their teeth and all their solid parts are still in a state of perfect 
preservation, and but slightly tinged with the coloring matter. At the present time, we have 
no similar deposits in progress extensively enough to determine whether organic forms flourish 
under such circumstances. The water flowing from chalybeate springs, and the ferruginous 
deposit originating from the same, do not apparently prove obnoxious to the frogs and fishes 
that inhabit the pools and streams. 
* A species of Fucoid consisting of long slender stems, vertical as to the strata, is found in the town of Penfield, Monroe 
county. 
