GEOLOGICAL SOCIETY OF DUBLIN. 
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Histioderma Hibernicum has not occurred to me at Howth, and affords 
one of my reasons for believing the fossils there to be different from those 
at Bray. 
These tubes appear to have been in texture similar to those of Tra- 
chyderma (Phillips), to which genus I at first referred them. An exa¬ 
mination of the specimens of Tr achy derma coriaceum , in the collections of 
the Museum of Practical Geology, Jcrmyn-street, London, and Museum 
of Industry, Stephen’s-green, Dublin, have led me to believe that the 
habits of these two worms were very different. I have, therefore, formed 
a genus of them, named from the membranous texture of their abode. 
Among the fossils from Carrick Mountain (C. W.) is one which appears 
to be a portion of one of their tubes; they have also an analogy to the 
tubes of Aphrodite, one of which is figured, Plate YIL, Pig. 4. 
The seas in which their mounds were formed must have been mode¬ 
rately still, and left uncovered by the tide for but a short period, as no 
remains of the rounded excreta of the worms are to be found, as would 
have been the case had the beach been left for any length uncovered, as 
we see occurs in the case of Arenicola piscatorius of our extreme littoral 
zone, when compared with the labours of the same animals near high 
water-mark. 
There are other markings in the Bray Head rocks which are probably 
Annellidan tubuli, lying in the same direction as the bedding; some of 
them twisted, but all rounded at the ends. These may be the casts of 
worms of a soft texture, but I have not satisfied myself at all on this 
point. A fine slab of them may be seen near the first wooden viaduct 
on the Wicklow line, near Bray, in a scratched rock. 
The Annelid tracks reported from Howth as “fucoidal” in their cha¬ 
racters resemble much the broken up tubuli made by Arenicola under 
the last-named circumstances. Pine specimens of all may be seen in the 
Museum of Industry. 
III. —Molluscan (?) 
The fossils thus called by me are raised tortuous markings, exactly 
similar to those so named in the carboniferous slates. They have been 
only met at Bray in a thin, green, gritty band, which traversed the red 
schist at the Ham’s Scalp; they may be, and I think probably are, rather 
Annellidan, especially since amongst them we find peculiar remains simi¬ 
lar to “ fucoids ,” which here at least, I think, must be looked on as the 
broken tube casts of a burrowing Annellid. The bed in which they occur 
is subjacent to a grit bed of rather tough texture, which was evidently 
formed in a muddy nook of the Cambrian Sea. 
Pine specimens of all may be seen in the Museum of Industry. 
There are other remains seemingly organic here, but of uncertain 
nature. Among these I may mention what appears to be the track of 
an Acalephe, but I am not sufficiently acquainted with the forms of impres¬ 
sions made by these in the recent state to speak positively. A. chrysaora 
makes an impression extremely like that to which I allude; also cer- 
