Identified by suffix/code "LY", most notably on Atlantic releases, ('LY' was the suffix used on many an Atlantic (and sublabel) LP and 45 starting in 1967 and continuing right through 1979 or '80.
LP releases on London Records and its various sublabels (Parrot, Parrot, etc.) as pressed by that plant, bore an 'SH' suffix after the matrix number as on the label
or "54" numerical code on 1979-84 pressings for PolyGram sublabels,
or by a backward embossed (Ƨ) in a circle (by 1979 without circle) in runouts (an embossed "X" in the deadwax if prior to 1968).
Another identifier are the 3.875" diameter center labels.
The plant was founded in 1947 by Clark Galehouse and named after his daughter, Shelley; prior to 1951 it was located in Roslyn, New York, before moving to Huntington Station. Besides pressing for a host of labels small, medium and large (including Columbia and RCA Victor), the company also owned two labels, Golden Crest and Shelley. Galehouse passed away in 1983, and the plant shut down in 1985.
Known to have pressed for Elektra, RSO