I've seen the "Is Mastodon prog?" thread here before but that was before the release of their latest offering 'Blood Mountain'.
If the scope and style of this release doesn't get them on the
progarchives then nothing will. If Death can get a mention then I
don't see how Mastodon 'doesn't' fit into the prog metal scene. The songs are certainly not on the long side (most over 4min with the last track at 20min) but the fusion of differnt metal styles and general experimentation of the release qualify it for sure. (IMHO) This is also at least their 3rd themed release.
Even if you don't agree get into their new one as it is awesome!
Go to their myspace for a full listen to the new CD.
Sorry for originally putting this in the wrong spot but all is good now. (I hope)