No. 50.] 
391 
pipestem and larger. These are generally not more than four or five 
inches long, and so arranged as to present a rude imitation of Hebrew 
characters. Along the Genesee river this group commences a short 
distance above Mt. Morris, and continues to the lov^^er falls at Portage. 
Along this v^rhole distance it may be seen rising into perpendicular 
cliffs, of from one hundred to two hundred and fifty feet in height, and 
is only partially obscured in a few places by land slides. From being 
more extensively exposed along the Gardeau Reservation than in any 
other place I have seen, I give this the name Gardeau, or Lowe?^ Fucoi- 
dal Group, in contradistinction to one above, next to be described. 
In following up the bed of the Genesee river from Mt. Morris to 
Portage, a place presenting an assemblage of magnificent scenery, 
scarcely surpassed, we find a decided change in the rocks, commenc- 
ing with the platform or table rock of the Lower falls. The sandstones 
below are fine grained, and generally one side covered with a glazing 
of shale, while the table rock has no glazing of shale, is coarse grain- 
ed, and presents a different aspect. The latter also abounds in a spe- 
cies of Fucoides, which for the most part is vertical, apparently having 
been growing on the muddy bottom, while the sand was deposited qui- 
etly around it, proving at least a nearly quiescent state of the waters of 
that period. This species of fucoid scarcely exceeds in size a com- 
mon pipestem, apparently very flexible, though we rarely find them 
curved. Occasionally, indeed, they appear as if the tops had been 
bent downwards and fastened to the bottom, while the sand enveloped 
them in that position, the stem presenting in the stone a portion of the 
circumference of a circle or ellipse. This species of fucoid is found 
in nearly all the sandy strata from the Lower falls upward to the top 
of the group, the upper rock of which is a mass of sandstone, more 
than one hundred and fifty feet thick. It is in this mass of sandstone 
that the tunnel for the passage of the Genesee Valley canal is being 
excavated. At the northern extremity of the tunnel, where the rock 
is uncovered, the surface presents numerous round dots, which are the 
ends of the fucoides, and which, on breaking the rock, are found to 
proceed downwards, developing the stem for many inches. At this 
place also, the surface of the sandstone is much worn and scratched, 
as if by a poweiful current, bearing heavy materials. This may be 
termed the Portage or Upper Fucoidal Group. There are no other 
rocks in the district better characterized by fossils than the two groups 
just described, and the fucoides are almost the only fossils contained in 
them. 
