NORTHAMPTON - Members of the former St. Mary of the Assumption Church in Northampton will press on in an effort to reopen their Elm Street institution, two years after its final service.

Last month, the Congregation of the Clergy in Vatican City turned down the appeal parishioners filed in January 2010 over Bishop Timothy A. McDonnell's decision to base a new, combined Northampton parish at the Sacred Heart Church on King Street, rather than at their own.

A spokesman for the parishioners says Roman Catholic officials may have misunderstood the thrust of their appeal.

"We believe the grounds were erroneous," Edward J. McMahon, a Northampton lawyer and former St. Mary's parishioner, said of the Vatican's decision last month. "We have no choice but to do this."

A Dec. 20 letter from Monsignor Antonio Neri, undersecretary for the Congregation of the Clergy, appears to suggest the Vatican believed St. Mary's members were objecting to the merger itself.

But McMahon notes he and others did not oppose the concept of consolidating Catholic churches in Northampton, which took place two years ago this month. Rather, they took issue with the bishop's statement that the cost of repairs at St. Mary's - the church that was initially to house the new parish - were prohibitive.

Their own calculations, based on estimates from building professionals, showed that work the bishop said would exceed $1 million - and led him to reverse his choice on a new home for the St. Elizabeth Ann Seton parish - could be done for much less money.

McMahon said a second reason cited in the Vatican's December letter also does not speak to the argument they put forward. "We are not totally dead in the water," he said.

If the parishioners are rebuffed again, their only recourse is to hire an Italian attorney, have their documents translated into Latin and seek to overturn the decision before the Vatican's highest tribunal, the Apostolic Signatura.