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PALEONTOLOGY: C.A.DAVIS 
1. A very considerable number of cellular, filamentous and gelatinous 
forms, which, from their methods of reproduction and general morphol- 
ogy, are clearly to be placed with the Blue-Green Algae — {Myxophyceae 
or Schizophyceae) . These include forms that show close relationship 
to modern types of these low Algae, not only in size and vegetative struc- 
ture, but also, many of them show a series of reproductive stages so 
characteristic as to fully establish their taxonomic relationships. In one 
instance at least, a minute but highly characteristic blue-green Alga 
has been found that can almost certainly be referred to a living genus, 
namely Spirulina. This fossil specimen is so well preserved and the 
measurements and form of the plant are so closely in harmony with 
those given in descriptions of one of the species of the genus, that one 
is tempted to identify the fossil as belonging to the same species, not- 
withstanding the hundreds of thousands of years which must have 
elapsed since the Eocene time. Other fossil species that may be re- 
ferable to existing genera are not uncommon. 
2. The Yellow- Green Algae (C/f/(7yi?/>Ayceae). Somewhat less common 
than the low forms already mentioned are plants that can be referred 
with more or less certainty to the Green Algae. Among these, both the 
cellular and filamentous types have been discovered, and, in a few cases, 
the identification may be said to be positive. Among cellular forms, is 
one in particular that so closely resembles a species of Pediastrum in 
all essentials, that its reference to this or a closely related genus is 
clearly not an error. 
Among the filamentous fossil forms classed as Green Algae, a type has 
been noted with spiral chloroplasts, so like those which characterize 
the well-known Spirogyra, that it appears at least to be a prototype, if 
not strictly a species of this genus. Other filamentous fossil species 
have been found which, because of structural peculiarities, can be safely 
placed among the Green Algae. 
3. Unclassified Algae. A large number of plants have been found, 
which, from their form and structure, appear to be Algae, but which as 
yet, cannot be classified among known living Algae. Some of these 
unclassified types are the largest plants so far found in the shales, and 
others are very minute. Some of the more noteworthy of the large 
forms seem to have been thin, gelatinous films growing on the surface 
of the detrital material which is now the imbedding magma. 
A very common and puzzling plant is one of the gelatinous film-like 
forms of considerable size, which seems to be without cellular structure, 
but which, nevertheless, has small areas on its surface which on magni- 
fication disclose definite, usually oval, spots covered with a net-like 
