Cob: Trouble finding fireclay

[Ryan Zwahr]

Hi,
Trying to build an earth oven per Kiko Denzer's book and I am having
problems finding fireclay (a clay soil alternative that he suggests).  I
live in Raleigh North Carolina, and I have a small lot and not really
anywhere for digging my own clay soil, short of ripping up my grass in my
yard, so I was trying to locate fireclay.  Nobody around here seems to know
what it is or where to buy it.  I have tried contacting brickyards, ceramic
and pottery supply stores, and the like.  Do you have any suggestions on
brandnames or other names that it may be called by.  I did find some mason's
cement, and portland cement at home depot, but I wasn't sure if they were
the same thing.  Can someone steer me in the right direction?  Please be
specific with the names of things I can use, since I am a "newbie" at this.
Also if anyone has other suggestions as to a material I could use to cob
with....

Thanks,
Ryan Zwahr
rzwahr at yahoo.com