p. 7

[6]

Some of the most interesting deposits of
this kind are found within. the limits of immediately west of
the city of Milwaukee; and it is from them
that the material is taken for the manufacture
of the much - celebrated cream colored brick
of this city. Such is the richness and beauty
of these brick that they are becoming an article
of export. Strangers upon landing here are
surprised that all the brick houses are painted the
same color - and such a beautiful color too; and
their surprise is not abated when informed that
they are not painted at all - the color being that
of the brick themselves. I take the liberty of
sending you for examination, specimens of these
brick, and of the clay from which they are made.

No fossils of any kind have yet been
discovered in these lake deposits. Concentric
concretions of an interesting kind are often found
investing the fibers of roots that have penetrated
the layers : more commonly the root has
decayed leaving only a small opening hole through
the centre. Figure 4 represents a portion of
one of these concretions broken off to show
the concentric circles. Their form is usually
cylindrical, tapering at each end. They are
much harder than the surrounding mass of
clay.