Jeffrey Adrian Boyan (January 15, 1947 - May 1, 2013), sometimes known as Geoff Bryan, was an American singer, songwriter and musician. He was the band H.P. Lovecraft's third bassist, joining the group in 1968. After the band split, he continued his solo career.
Jeffrey Boyan in "The Fillmore Shoggoth"
Jeff had just joined the band HPL as a bassist and vocalist in the Spring of 1968, when they got a gig at the Fillmore in San Francisco. It was a somewhat ominous time for the country; in addition to all manner of political unrest, an iceberg that had broken off from the Ross Ice Shelf in 1966 had finally made its way north, without melting, to the San Francisco coast line.
Arriving in the city early in the day, the band decided to go to San Francisco Zoo to see the cave penguin exhibit. After leaving the zoo, the band bought lunch and then went on to the Fillmore to rehearse. The band was surprised to see a pair of Old Ones in the audience. Jeff confirmed that with the Old Ones was famous author Howard Phillips, who'd written extensively on the Miskatonic Antarctic expedition that first alerted humans to the existence of the Old Ones. Phillips' wife, Sonia, was also present.
The presence of the Old Ones prompted the band to actually give a good rehearsal. The Old Ones enjoyed the music. Phillips was not as enthusiastic in his praise.
During their performance that evening, the house emcee announced that the iceberg had landed near the Zoo, and deposited shoggoths in the city. The Fillmore began to evacuate, but then a shoggoth arrived, which decapitated both of the Old Ones and then Howard Phillips in short order. The shoggoth was destroyed by napalm, and then the band helped evacuate the grieving Sonia Phillips to nearby Lafayette Park.
After eating and sleeping through the night, Jeff was the first member of the band to wake up the next morning.
While Harry Turtledove never gives "Jeff" a last name, he provides enough clues in the story to confirm that Jeff is indeed meant to be Jeffrey Boyan.