By 1977, the Grateful Dead had grown beyond their infancy phase and into that of a well-established part of the American arena rock machine that would define the decade in pop culture.

The band had blossomed from their psychedelic obscurity in the latter half of the 1960s into a powerhouse of group improvisation and musicianship by the time resumed touring in 1976. Come 1977, which many critics and Deadheads consider one of the band’s strongest years, the band was about to release one of their strongest studio albums yet–Terrapin Station.

During a February 26th, 1977 concert at the Swing Auditorium in San Bernardino, CA, the Dead treated fans in attendance to the live debut of two new originals that have gone on to become fan favorites, “Terrapin Station” and “Estimated Prophet”. Both tracks would go on to appear on the band’s Terrapin Station album when it was released in July 1977.

Related: Grateful Dead Studio Albums Ranked Worst To Best

Written by Jerry Garcia and longtime lyricist Robert Hunter, “Terrapin Station” evokes classical poetry with lines like “Inspiration, move me brightly” and “In the shadow of the moon” to match its climactic musical suite. “Terrapin” is certainly one of the more renowned works within the Grateful Dead songbook, as it takes the listener on an active journey through numerous key and time signature changes on its way toward its trademark finale.

As for “Estimated Prophet”, the song penned by Bob Weir and the late John Perry Barlow arrived with its reggae-inspired 14/8 time signature, complete with a bouncing groove that’s almost too funky to resist–A “fire wheel burning in the air,” if you will.

Relive the live debut of these two Grateful Dead classics from 1977 via the audio player below.

Grateful Dead – Swing Auditorium – 2/26/77

[Audio: Jonathan Aizen]

Setlist: Grateful Dead | Swing Auditorium | San Bernardino, CA | 2/26/77

Set One: Terrapin Station*, Minglewood Blues, They Love Each Other, Estimated Prophet*, Sugaree, Mama Tried, Deal, Playing In The Band > The Wheel > Playing In The Band

Set Two: Samson & Delilah, Tennessee Jed, The Music Never Stopped, Help On The Way-> Slipknot!-> Franklin’s Tower, Promised Land, Eyes Of The World-> Dancin’ In The Streets-> Around & Around

Encore: U.S. Blues

*first time played