George L. Carlisle, Clay County clerk for the last 32 years, and the rest of the old guard courthouse crowd did not see Chance Irvine, Ann Wiggins and Dorothy Holt coming.

That is not surprising. The three middle-aged women are not the kind of politicians a county controlled by a good ol' boy network of Democrats ever since Reconstruction was accustomed to.

Who would have ever thought Wiggins, a high school English teacher with a Brooklyn accent, could be elected school superintendent in north Florida "cracker country?" Or Irvine, who moved from Illinois a decade ago, state representative? Or Holt, a native of upstate New York, superintendent of elections?

But two years ago the insurgents all won. They did so by capitalizing on a population boom that transformed much of Clay County into an affluent bedroom community for nearby Jacksonville.

"It was a real coup, almost a made-for-television melodrama," said Holt, who had never run for anything beyond president of the local chapter of the League of Women Voters. "We weren't only three women. We were Republicans."

"A few years ago it would have stretched my imagination to even dream something like this could happen, but the county has changed," said Evelyn B. Cooper, county Democratic Party chair. "The Yuppies are taking over. It is something we Democrats are going to have to reckon with."

Newcomers are helping change the face of southern politics, especially in the suburban rings around the region's major cities. Name almost any southern city -- Atlanta, Richmond, Charlotte, Columbia, New Orleans, Mobile, Orlando, Memphis -- and a suburban Republican stronghold can be found nearby.

This is especially true in fast-growing Florida, expected to become the nation's fourth largest state by 1990. A study last year by the Survey Research Center at Florida State University found Republicans outnumbered Democrats 39 percent to 26 percent among those moving into the state during the last 20 years, and "changes among the youngest Florida voters have the potential of making a significant impact on the future of Florida politics."

"The story of the South the last 20 or 30 years is one of a lot of Yellow Dog Democrats dying out and a lot of new people moving in," said Houston-based pollster Lance Terrance, a Republican. "The demographics aren't in favor of Democrats," said William Hamilton, a Democratic pollster.

In few places are the lines drawn so clearly between the old and new as in Green Cove Springs, Fla., once a sleepy little farming and retirement town perched on the blue waters of the St. Johns River. The Democratic Party here is the party of tradition, a monopoly institution for more than a century. Personal ties, not ideology, decided elections.

County Clerk Carlisle has held office 32 years; the county sheriff 20 years, the county property appraiser 16 years. One county commissioner recently retired after 32 years; the school superintendent who Wiggins defeated had been in office 20 years.

"The people who have been here years and years are the backbone of our party," said Democratic Chair Cooper.

The GOP, led by a corps of energetic women and young professionals, is the newcomer's party. "Our real strength is the young people," said state Rep. Chance Irvine, elected with the slogan, "You deserve a Chance for Better Government."

Democrats initially dismissed her victory and that of Wiggins and Holt as a fluke. They blamed their defeats on Reagan's coattails and internal fights in their party.

That ignored the strength of the three women. Each was an attractive candidate, articulate and intelligent. Wiggins headed a high school English department and held a master's degree in administration; Holt had an impressive record of civic work; Irvine, the most experienced politician, had worked in GOP campaigns for years.

It also ignored change in Clay County. Once rural and sparsely settled, the county's population doubled during the 1970s. Thousands of younger, more affluent and better-educated voters moved into new homes, most in the Jacksonville suburb of Orange Park. Today only one resident in five is over 44 years of age; 22 percent of the families depend on nearby Jacksonville Naval Air Station and Cecil Field for jobs, according to the county Chamber of Commerce.

It took a second upset victory by a Republican in a special state Senate election in March to convince most Democrats that they had a problem.

Democrats fielded a well-known former Senate president, Lew Brantley, and brought in the state party's heaviest hitters -- U.S. Sen. Lawton Chiles, Gov. Robert Graham and House Rules Committee Chairman Claude Pepper -- to campaign for him.

Brantley outspent Republican Ander Crenshaw, a personable 41-year-old investment banker, by 2 to 1, but still lost decisively.

"I'm predicting we won't have any Democratic elected officials in Clay County in 10 years. I don't see any stopping us now," said Dr. Glenn Gidseg, 34, one of the energetic young professionals who have taken control of the county GOP organization. "The Democratic Party left the Democrats. People down here haven't realigned. They've just found it's okay to vote Republican."

"Republicans are a long way from taking over Clay County," Carlisle, a prototype of the old southern politician, declared as he leaned back in his chair in the county courthouse. "So many people nowadays are voting the man rather than the party."