The James Gang had its roots in the Woodstock era, and the trio’s 1969 debut forms a bridge between the decades. The trio bears the unmistakable influence of the bands it opened for in the ballrooms around Cleveland and Detroit. A slow-building collision of strings and guitar, “Collage” anticipates the sound Led Zeppelin would turn to in the years to come, while a wooly romp through the Yardbirds’ “Lost Woman” borrows a lot from Cream, especially the soloistic assaults of bassist Tom Kriss. For all their ideas, the Gang’s greatest strength was their ability to rock, even in this early incarnation. A cover of the Buffalo Springfield’s “Bluebird” trades the original’s dreamy atmosphere for a blast of pure guitar, and “Funk #48” is a tasty prelude to its better-known sequel, “Funk #49.” The band was still finding its voice among the legions of shaggy rock groups, but their reading of “Stop” shows why they wowed crowds. Originally a Georgia R&B hit for Howard Tate, the Gang’s version splits the difference between a Macon roadhouse and a Cleveland rubber factory.