In all my years of concertgoing, I have never heard a stage utterance more bad-ass than "Shut your stupid mouth before I splatter your brains all over the floor!" This was Jerry Lee Lewis’s response to a fan at North Shore Music Theatre who shouted for one request too many. Spoken under his breath with a no-joke tone, Lewis’s retort offered one possible explanation of why he’s called the Killer.

Performing before a fairly sedate audience in Beverly a week ago Tuesday, Lewis and Little Richard proved a study in contrasts — but then, they always did. And they’re currently part of a very short list of first-generation rock-and-rollers who still perform. Chuck Berry and Bo Diddley are still out there, but they’re getting more out-there every year. Fats Domino is still great, but he never plays outside New Orleans. And the Everly Brothers, who were magnificent to the end, retired two summers ago. Whether or not they’ve still got a whole lotta shakin’ left in them, Lewis and Richard are close to being the last ones standing.

Now pushing 70, Lewis is long past kicking over piano stools or pounding the keyboard with his feet. His old powers are most likely to come through on the slower blues and country tunes. At NSMT, "Trouble in Mind" sported a convincing vocal and one of his trademark barrelhouse piano solos. And though he didn’t play a full version of the obscure goodie "Burnin’ Up," it was a kick to hear part of it. But there were also a lot of sudden stops and long pauses between tunes; at one point he mistakenly restarted a number that he’d just played. His best rocker was a Little Richard tune, "Lucille," after which he sheepishly (and not too convincingly) said he hadn’t realized that Richard was on the bill. Lewis was doing solid shows as recently as 1995 (when his last studio album, Young Blood, with members of NRBQ doing back-up, was released on Sire). Last week’s show wasn’t one of those, but you probably wouldn’t want to tell him that to his face.

And Little Richard? Still great, still crazy, and still wearing more make-up than a houseful of Hedwigs. "That was my 70-year-old scream!" he announced after one of the night’s first high notes. "Isn’t it great that I can be old and still be beautiful?" When he brought audience members on stage to dance, it sounded as if he were about to build an ark ("Gimme two black people! Okay, now I want two Jews! And now, two fat people!"). And for a social statement, he played Chuck Berry’s flagwaver "Back in the USA" — which, he noted, he started performing "after that 9/11 thing happened."

Entertaining as it is, Richard’s flamboyant shtick can be a fallback when he doesn’t feel like putting out, as was the case when he played the Newport R&B Festival in the late ’90s. But the North Shore gig had more of the real stuff, as he brought a nine-piece band (complete with two drummers) patterned after his classic ’50s outfit, the Upsetters. Perhaps because Lewis had dared to play the tune, Richard did a vintage-sounding "Lucille," singing verses that he often skips over. And he pulled out two semi-obscurities: "Bama Lama Bama Loo" (an England-only hit that Elvis Costello covered) and the swamp-bluesy "Send Me Some Loving." Although he rushed through "Tutti Frutti" and "Long Tall Sally" — as would anyone who’s been playing those tunes for half a century — his screams sounded impossibly close to the ones on the records.

How long Richard can keep this up is anyone’s guess. It’s worth noting that last year on Politically Correct, he told host Bill Maher he was about to retire. But it’s also worth noting that he said the same thing in 1958.