snippet history of 'that useful substance' in America

[Mark Kohut]

"Joe mentions PCP, recalling a batch of that substance that moved through Fort Worth, Texas in the late 1971-early 1972 period, introduced as "synthetic THC"," 

A quick perusal of snippets online of a couple--three histories of drugs in America, mentions that PCP entered @ this time period....

And, the histories indicate that the mass heyday of pot--'that useful substance'-TRP---was around the time C of L 49 is set and @ when
Inherent Vice ends....(before that, mostly in musician circles), after that, other, harder drugs were on the rise and were dominant in the society at large.