Sadly, Lanier Greig, one of the "original" members of ZZ Top passed last week at the age of 64:

http://www.chron.com/news/houston-texas/houston/article/Greig-early-ZZ-Top-member-dies-at-64-4284956.php

The original ZZ Top lineup in 1969 consisted of Billy, Lanier Grieg on keyboards, and Dan Mitchell (from the Moving Sidewalks) on drums.

Check out "Salt Lick" featuring Lanier on keyboards (with Billy overdubbing the bass):

http://www.youtube.com/watch?v=dfjAcPRrFfE

Mr. Greig kept busy after the ZZ days He was an accomplished musician,and worked for decades as a session musician.

Someone graciously just posted this video of Lanier's playing.

http://www.youtube.com/watch?v=_6QdTECaQVE

RIP Mr. Grieg