it's a variation on the ideas found in dazed and confused
but sounds like E-E'-Eb-D-B-Bb-A-G-A for the main bass riff
in the preamble to the housing it is an Em chord then the riff is D-E-D-E-D-E--D-E-G with power chording of D[sup]5[/sup]-E[sup]5[/sup] following the riff
in the housing section the riff is E-E-A-B-D--B-D-B-A and the chording is Em-D