Being inside Memorial Coliseum for last night's Joni Mitchell concert made you a member - or visiting alien, depending on your age and attire - in the Lexington chapter of the American youth microcosm, population about 12,000.

From pre-teenyboppers to aging hangers-on, it was a gentle mass of gum-cracking, grass-smoking, cola swigging individualists gathered for the one thing best able to bring young people together in the 70s - music.

From the outside it looked like more Wildcat basketball in the offing. Cars were parked in every available nook and cranny within six blocks. Lines of people snaked along dark sidewalks and across parking lots to the turnstiles. But, strangely, there were few youths lounging in the burger establishments next door and down the street the Campus Arcade was almost silent and empty (unlikely scenes even if basketball tickets were being given away.)

At the ticket window, worried young faces at the back of a murmuring queue watched as the last good seats were being sold.

"Stop South Hill Parking" leaflets got a quick glance and fluttered to the lobby floor, unable to compete with reverberations of the L.A. Express that were drawing the crowd up the ramps and down into their seats.

But contemporary concert-going means seeing, hearing and being seen.

The coliseum's concourse was filled with a continuous Easter-type parade of the latest styles (if it's comfortable, wear it). Jeans are the basic uniform. Beads are still big. A ring in your nose seems to be catching on. What looked like a real innovation turned out to be a carpenter's apron on a concessions employee who used the pockets for change.

"Do your parents know you're here?"

"Well, sort of," she said. (She being probably about 13.) "I told my mother I was going to UK...to the library for a class project."

Other young girls passed unflinching through the glances of much older college guys. Obviously they'd been here before.

A high schooler casually carried a can of beer through the crowd, getting it under his jacket as a policeman rounded the corner.

"Ever have any trouble at these things?"

"Naw, biggest thing is an occasional fight."

A cloud of marijuana smoke wafted by.

"How about dope?"

"Depends, sometimes we just take it away and send them back to their seats. We arrest a lot too."

The L.A. Express is winding up their 45-minute warm up. The concourse really fills up. Joni Mitchell's two-hour set won't sound good from the restroom.

"Excuse me, is this the west side? I said excuse me, hey fellow!"

The elderly usher turns around. He has a radio earphone in one ear and an earplug in the other.

"You always wear those?"

"Just when the 'Cats are playing. Other times I have two earplugs."

Pre-Joni Mitchell conversation ranges from dropping classes to a TV commercial about a mint "that really does shake up your mouth."

Joni's a little late and a spattering of handclapping and whistles ebbs back and forth.

Then the lights go out, Joni's on stage and American youth has suddenly got it altogether again.