This came out in 2002 – or at least that’s when I got it. Here’s what I said about it back then (with some minor editing):
Their name conjures up images of some sort of lumbering, slow-witted prehistoric beast.
But while hard-hitting metalloids of Mastodon boast the massive power and thunderous ferocity of their namesake — and while they do lack the blinding speed of other inhabitants of the metal jungle — they are in no way primitive throwbacks. Anchored by two former members of noisy avant-metal outfit Today Is The Day, Mastodon take a similarly ambitious approach, combining the technical intricacy and precision of classic Rush or Metallica with the relentless bash ’n’ grind of power-metal — and then topping it off with vocals that resemble the battle cries of a wounded Cro-Magnon. Perhaps they’re the next step in the evolution of metal.