Somewhere in the Happy Hunting Ground way up above the now sovereign State of Connecticut flits an unhappy Indian spirit, unhappy not because he has been a spirit for possibly as many as 10,000 years, but because his sloppy workmanship is now on display before the contemporary latecomers now occupying his former lands. Two miles down the road from here in the Litchfield Hills of Connecticut, the American Indian Archaeological Institute displays as its prize exhibit a fluted projectile stone point from the Paleo-Indian period, dug up only last year.

The point has been authenticated and carbon dated as being 10,190 years old, give or take 300 years. There has been evidence that men lived on this hemisphere around that time and even earlier, but this is the first proof that men lived in New England and in Connecticut as early as about 8,512 B.C., before there was even a Yale University or lock, or Pilgrim fathers and mothers.

This historic stone point is not perfect; in fact, its imperfection is probably why it was found in a dig beside the Shepaug River in whose valley stands the Institute's new and very attractive home and museum. The point is broken in two and one can conjecture (which is what archeologists do, possibly a little more scientifically) that the Indian, with the point three-quarters shaped, threw it down in disgust when it broke while he was working on it.

The two pieces, together just a couple of inches long, were found only a couple of feet apart but about five feet below the earth's surface. They were in the company of enough stone chips and other bits of evidence, including two smaller, wellcarved points, to indicate that this Indian, and possibly some fellow tribesmen, had a long time ago sat around a fire shaping stone points for spears and arrow tips against the opening of the hunting season. If it had not broken, this stone point probably would have disappeared in a forest somewhere in pursuit of some paleolithic game.

It was because of the charcoal in its immediate vicinity that the Institute was able to have the point's age carbon dated so precisely. It is so old that dating it just about reached the maximum span of carbon dating. To reach further back in history via dating, scientists are now trying to develop other dating processes.

Although the fluted point is, to make a point semantically, the high point of the Institute's short and happy life, it is by no means all of it. The Institute's history, according to Edmund K. Swigart, president and one of its founders, starts only 10 years ago when it was organized by seven friends, resident in and near the Shepaug Valley and interested in discovering more about the earliest American Indians. They were motivated not only by scientific curiosity but also by the belief that since the primitive Indians had come to terms with nature and their environment, perhaps we might today learn things of value to us from their lifestyle and value systems, things like how to use our natural resources wisely.

In 1971 the group incorporated as a tax-exempt organization called the Shepaug Valley Archaeological Society and by 1972 it had raised $300,000 privately, most of it among local and nearby residents, to build a reserach center on 15 acres of woodland purchased from a local woman proud of her Indian ancestry. Connecticut Indians helped build museum exhibits, as did members of the Schagticoke Tribe who occupy a 400-acre reservation in nearby Kent, and in July 1975, the Institute moved into its museum and research building.

Long before last summer's exciting proving of the correct age of the broken stone point, the Institute's fame had spread around this country and the world. It has already welcomed visitors from 46 of this country's 50 states and from 50 foreign countries, ranging from Russians to Indians from Peru. As Swigart noted, it is probably better known abroad than it is at home, although American tourists last year began discovering the Institute.

Eight thousand Connecticut school children have visited the museum and walked its fairly short but eon-spanning Habitats Trail, where markers indicate historic time zones. A tundra site is to be reconstructed to show the Arctic-type tundra of New England right after the glacial period ice sheets receded, and from there the trail will lead through ancient and modern trees as well as shrubbery known and used by the Indians for food and medicine.

The Institute stepped out of its obscurity with a televised press conference last August to report the dating of its great find. And the resultant increase in visitors from all over the country makes officials predict a total of 25,000 visitors in 1979.

That will be a lot because this is a small museum, in a building already crowded. The structure is so neatly fitted into the thick stand of trees on its property that one has to look carefully at first to find it. The first display case the visitor sees is the one containing the oldest fluted point and some of the items discovered with it.

Incidentally, thatdiscovery was made by a rank amateur, a volunteer on his very first day at the dig just east of the museum above the bank of the Shepaug River. Dr. Roger Moeller, the Institute's research director, had just shown the young man how to scrape a film of earth away with each sweep of the trowel, and was walking away when he heard the faint clink of metal on stone that is music to the ears of the archaeologist. He whirled and found the novice digger with half of the precious stone point in his hand.

Around the corner from this exhibit stands a 12,000-year-old giant mastodon, or rather its skeleton, a gift to the Institute from Yale University's Peabody Museum. Thereafter come the cases and shelves of Indian artifacts, tools, implements of all kinds and beyond them a full-size Longhouse 20 feet long and 16 feet wide, adequate for a single Indian family unit. Educational films are shown to groups in a small classroom-auditorium. On the way out, visitors can buy authentic Indian handicrafts, made in the old ways by Indian men and women who now live in Connecticut.

While as most museums, the atmosphere seems static and leisurely, in the scientific workrooms beyond the exhibit spaces the small staff is working feverishly on many related projects. And the minds of Swigart and Dr. Moeller are churning at full throttle with a sense of urgency that explains the Institute's great growth in its few short years.

"Time is short," Swigart said. "Every day we are losing sites we need -- losing sites to highways, bridges, building construction. We have only 10 years to get the story of early Indian life in Connecticut. This is the greatest detective story in the world -- human history."

He is speaking particularly of western Connecticut and the valleys of the Shepaug and of the parallel Housatonic River. Connecticut Route 7 now runs north from Danbury in a short spur of nice (for the motorist) divided modern highway, and it is only a matter of a few years before the politicians and landowners agree on the rights of way to extend this expressway northward. According to Swigart, it probably will be right up the Houstonic River Valley, and while construction work may uncover some archeological surface information, the new highway will permanently seal many other extremely valuable dig sites under thick layers of concrete.

Racing the clock and this fast-approaching concrete glacial age, the Institute's staff is planning to expand its digging up and down the Housatonic River and also the Shepaug in the coming years to recapture as much of the past as possible. A great many volunteers will be needed to man all the digs anticipated throughout this region. Many will be recruited through Earthwatch, an environmentally oriented organization that lines up volunteers for such projects, and many others will come from colleges and schools of New England and throughout the country.

In this race against time, money is essential, and the Indian Institute is turning to the public -- especially tourists and lay people interested in Indian history. It tries to avoid federal grants because Washington ties many strings to its grants, conditions of who may be employed and how, and how paid, whereas the Institute does not want to abdicate its control of its scientific work to non-scientific regulations.

The Institute does not charge admission but asks donations from its friends and visitors, suggesting 50 cents for teen-agers, $1 for adults. Only 50 percent of its visitors so far have contributed, 12,000 visitors last year donating only $5,000.

Throughout the year there are courses of all kinds in Indian lore, crafts and artifacts, and the like. These are attended mostly by Connecticut residents, although many archeology students come here for serious study. The Institute is open Monday through Saturday from 10 a.m. to 4:30, Sunday 1 to 4:30 p.m.; closed Christmas, New Year's Day and Thanksgiving.

In keeping with its academic atmosphere, the Institute posts only a very small sign on the west shoulder of Route 199, about two miles south of Washington. Motorists will do best to target in on New Milford, Conn., whence secondary roads wind through beautiful New England hills and woodlands to Route 199 and the museum.

It is difficult to tell who is responsible, the early Indians or the early settlers, but this part of western Connecticut is literally awash with antique shops, so proliferated that one must wonder how the modest population of early America could have manufactured or purchased and used all those pieces of furniture, decor and bric-a-brac. It makes a non-New Englander wonder about all those tales of shrewd Yankee Traders and Connecticut's wooden nutmegs.

For copies of the Institute's publications and information about exhibits, classes and special programs, write the American Indian Archaeological Institute, P.O. Box 85, Washington, Conn., 06793.