Investigators on Monday had not determined the cause of a large fire that erupted late Sunday at Saugatuck Congregational Church and, over the course of six hours, inflicted heavy damage on part of the historic house of worship.

Meanwhile, church officials assessed the extent of losses and quickly cobbled together alternate arrangements for their annual Thanksgiving community celebration amid an outpouring of support.

Investigators from the state fire marshal's office have been on the scene, along with Westport police and fire officials, checking severely damaged areas at the rear of the church complex at 245 Post Road East. The most heavily damaged sections housed church offices, meeting rooms and a nursery school.

The 179-year-old landmark sanctuary appears to have escaped serious damage from the main body of the fire, suffering primarily from smoke and water collateral damage.

"It takes a lot of time to sift through the damage," said Westport Fire Chief Andrew Kingsbury. "They need to be diligent in their determination of the cause and origin of the fire."

By Monday afternoon, however, Saugatuck church officials had secured another site for the annual Thanksgiving feast and community gathering, which traditionally attracts more than 300 people. It will be hosted at 1 p.m. Thursday by another downtown house of worship, Christ and Holy Trinity Episcopal Church, 75 Church Lane.

"We've been blessed since we've had so many offers" of help, said Mary Ann West, the church's communications director. "We look forward to using their space."

Among the casualties of the fire were 30 turkeys for the event that had been dropped off at the church Sunday evening, but offers of new turkey donations appear to more than make up for that loss, West indicated Monday.

Church officials were unsure Monday about the extent of damage to church records in the offices.

Ellen DeHuff, director of the Saugatuck Nursery School, which had to be closed because of the fire damage, said school officials are considering using portable classrooms or temporarily relocating to another site, but no decision has been made yet.

The nursery school had not scheduled classes this holiday this week, but Huff doesn't expect that they'll resume by next Monday.

"I don't think this is going to happen overnight," she said of finding a new site for the nursery school. "We're researching our alternatives."

In a "Dear Friends" letter emailed Monday, Saugatuck church leaders wrote: "We are clearly hurt by this, but we are also profoundly thankful that the fire did not, as we feared it might, take the entire building. We have not lost our spiritual home.

"At this time we know that there was severe fire damage to the choir loft, the Daniels Room, the Fellowship Room and the nursery school. We know that the sanctuary and the new education wing have at least sustained water and smoke damage. At this time, we don't have more details on the extent.

"We've had so many expressions of support. Sarah Verasco, Jeff Ryder, John Branson and the Town of Westport, along with many others, have stood with us through this ordeal.

"So many others have come to visit or called to express their concern and support, and we know that our friends are praying for us across the state and even the entire United Church of Christ. May their prayers comfort us as we step forward ..."

A Westport business, Britt-Air, donated 15 turkeys to the cause Monday morning.

Scott Thommen, owner of the local heating and air-conditioning company, said, "I know a lot of people are hurting during the recession, and with the fire, even more so.

"I just want to help however I can, said Thommen as he dropped off the turkeys at Oscar's Deli on Main Street, which has volunteered to store the fixings for the Thanksgiving feast.

In addition to storing the turkeys, Oscar's owner Lee Papageorge is serving as the gathering's dessert manager.

Oscar's kitchen also stored turkeys before the church's feast last year.

"It feels good to be able to help out," Papageorge said.

More later on www.westport-news.com