Berkeley Pit Lake in Butte, Montana, is an acid mine waste reservoir rich in toxic metals. A Pithomyces sp. isolated from the Pit Lake yielded three tyrosine derivatives (1-3), one of which acts as a 5-HT(2a) receptor ligand. This type of activity has been associated with migraine preventative and antihypertensive drugs. The isolation and characterization of compounds 1-3 and three sesquiterpenes (5-7) that have been isolated previously from higher plants are reported here.