The Mugwumps basically are notable for what its members did after they left this short-lived quartet. Cass Elliot and Denny Doherty formed half of the Mamas & the Papas, while Zal Yanovsky was the Lovin’ Spoonful’s founding guitarist. (The fourth Mugwump was Elliot’s then-husband, Jim Hendricks.) These tracks, recorded in two days during August 1964, were released by Warner Bros. in 1967 after the band members found success. You can hear why this group isn’t better-known. Their pre-folk-rock music often feels rather tentative. Their crisp vocal harmonizing occasionally sounds square, and some arrangements comes off dated, while Yanovsky’s electric guitar playing projects a hipper, Greenwich Village vibe. Still, this historical curio reveals a promising band. The singing on “Everybody’s Been Talkin'” suggests what the Mamas & the Papas became, and the better songs here — notably Felix Pappalardi’s “Do You Know What I Mean” — impressively meld traditional folk with rock ‘n’ roll.