NEOZOIC INVERTEBRATES 
IO3 
probably not greater than that between the Chickasawan 
and Claibornian horizons in the standard Alabama column, 
to which we are accustomed to refer our correlations of 
the Eocene horizons of the east American Tertiaries. 
Five species were obtained from the lower beds, one 
being the Venericardia flanicosta Lamarck, the well 
known 6 finger post of the Eocene ? which, with two others 
of the five, was also obtained from the upper beds. 
Owing to the poor condition of the fossils and the fre¬ 
quent deformation of the casts by shearing, a number of 
the species are here determined only generically, it being 
thought best to defer naming specifically material which 
might lead to confusion when better specimens turn up at 
some future time. 
As is natural, a large proportion of the species appear 
to be new, and of these eleven seem to be in condition 
which renders it safe to describe and name them. 
An enumeration of the fauna obtained by Dr. Palache 
now follows. 
LIST OF THE INVERTEBRATE FOSSILS 
PORIFERA 
Cliona alaskana Dali. 
Locality . —Upper beds, 3373. 
The numerous oysters which occur in the tough greenish-black 
shales of these beds are frequently dotted with minute circular holes 
closed by matrix. On breaking them open the interior of the shell is 
seen to be excavated by numerous inosculating galleries, sometimes 
merging into irregular cavities with rugosely curved walls. These are 
the work of the sponge Cliona which, in its younger stages, forms 
these burrows in the shell, the water and the food it bears finding 
access to the sponge through the small circular orifices above men¬ 
tioned. In the absence of the sponge itself or its spicules it is of 
course impracticable to enumerate distinctive specific characters, but as 
the borings are quite recognizable and the species was doubtless dis¬ 
tinct from the recent Cliona sulfurea, it may for convenience of refer¬ 
ence take the name Cliona alaskana . 
