A first dip into the heady waters of prog, Rush’s third album ends with two portentous works—“The Necromancer” and “The Fountain of Lamneth”—that push their songwriting past blues rock and into grander pastures. This is pugnacious, dramatic music with winsome interludes. The punchy hits come fast and early: “Bastille Day” is all razor-guitar and attitude, with Geddy Lee’s vocals reaching past metal raunch to folkish purity, while “I Think I’m Going Bald” and “Lakeside Park” ooze metallic funk.