From the crest of the Blue Ridge mountains, where the forests shimmer in the red and gold headdress of Indian summer, you can see two Virginias.

To the east is the familiar Old Dominion of affluent suburbs, high-tech industries and bustling military bases, where unemployment is all but unheard of and the chief economic question is "How fast are we growing?"

To the west is another country. One-fifth of the state lives on the far side of the mountains in 15 counties that are geographically and economically apart from the rest of Virginia.

West of the Blue Ridge, Virginia is "an area whose economic development potential has yet to blossom," says Beverly Fitzpatrick, vice president of Dominion Bankshares of Roanoke. The view from the mountaintop looks different to Virginians who come from opposite sides of the ridge, he reminded Shenandoah Valley business executives, who spent an afternoon at James Madison University in Harrisonburg last week assessing the economic outlook for their region.

What Fitzpatrick and other Valley business leaders see is a region whose economy is more like the middle-class Middle West than McLean, Fairfax or Alexandria. The Valley is recovering from the last recession more slowly, they say. It is suffering more from high interest rates and imports. Its future is linked more to its own bootstraps than to the pull of government spending that holds up the economy of the rest of the state.

When you take away Northern Virginia and the military from the state's balance sheet, "you have a rather ordinary economy," said Dr. Ronald Carrier, the economist who is president of James Madison.

"We do not measure up to the Sunbelt states very well," noted Carrier.

Since he became president of James Madison, the Harrisonburg school has doubled in size and grown even more in stature. Carrier says further investments in education and research are what the state needs.

The Center for Innovative Technology now being developed by the state in Northern Virginia and the multimillion-dollar nuclear accelerator the federal government plans to build in Tidewater are critical investments in Virginia's future, he specified.

"We are now developing at the state level an agenda for economic progress that will enable us to benefit from the type of economy we are going to have in the 21st century," said Carrier, noting that by his reckoning, "the 21st century will probably begin around 1990."

The 21st and 19th centuries already meet west of the Blue Ridge, where 20th century mountaineers may live in log cabins and work in state-of-the-art laboratories.

W. L. Braun, president of Comsonics Inc., a Harrisonburg company that makes electronic gear for the telecommunications and cable television industries, worries that the future is endangered by computer chips that haven't been invented yet. The Japanese are leading in development of high-density computer memory modules that will power 21st-century machines, he warned.

Shortages of technically trained people and the high cost of capital can limit the growth even of companies like Comsonics, which last year was named one of the fastest-growing firms in America.

Comsonics had 90 people on the payroll last January, is up to 120 now, will have 150 employes by next year and will open its first branch in 1985. Still, Braun is apprehensive.

Up and down the valleys of the Shenandoah rivers are dozens of businesses that have built a diversified manufacturing economy west of the mountains and will power the future of the region's economy.

Another company that is expanding within the Valley is O'Sullivan Corp., a Winchester firm that call itself "a manufacturer's manufacturer" because it makes parts and materials that go into consumer products.

The grills for Dodge Omnis, the heels on 25 percent of all the shoes made in America, the vinyl on most three-ring binders and the plastic rear windows on most U.S.-made convertibles and dozens of other products come from O'Sullivan plants, explained Executive Vice President James Holland.

"We see a very positive economic outlook," he added, listing a 60,000-square-foot plant addition under construction now and two more expansions already committed for next year and the year after.

It is companies like Comsonics and O'Sullivan that will provide the jobs of the future, stressed Fitzpatrick of Dominion Bank, sponsor of the annual Valley Economic Seminar. "Eighty percent of new jobs will come from current industries," he said. "We need to make sure they stay here and don't move."

Virginia west of the Blue Ridge can no longer count on agriculture to fuel its future, said James Cisney, executive vice president of the Rockingham Cooperative Farm Bureau. Though the farm economy and agribusiness grew through the '70s, both are cooling off now.

Neither dairy nor beef cattle, hogs nor laying hens can turn a profit for farmers this year and the apple crop "is not necessarily as good as they thought it was going to be. The sizes are small and the bushels are down," said Cisney.

"I have never seen the agriculture community in the low state of cash flow it is in for 1984 and looks like it will be in 1985," he lamented, echoing agricultural ailments that plague most of the nation's farm counties.

The growing industries of the Valley are able to take up much of the agricultural slack, but the result is an economy that is more accurately described as comfortable rather than affluent.

The pace of life is slower west of the Blue Ridge and the people who understand its economic lifeblood best say things are not going to change quickly.

"I don't think 1985 is going to be much different than 1984 for the Virginia economy," said James Madison President Carrier. "We can sustain economic growth," he added, "but to make more than a blip on the screen, we will have to do more."