A Baltimore Circuit Court judge extended for 45 days yesterday the state's conservatorship of First Maryland Savings and Loan despite the revelation that the state has encountered a "significant obstacle" in selling the thrift.

"Though I am a bit concerned about the status of First Maryland and whether it can be disposed of as a going entity to another institution, I see enough light at the end of the tunnel to extend the conservatorship for 45 days," Judge Joseph H.H. Kaplan said.

The extension means interest-bearing accounts at the Silver Spring thrift will continue to pay 5 1/2 percent interest.

Certificates of deposit will continue paying interest at a higher rate.

The 22,354 depositors of First Maryland have had their $281 million in deposits frozen since Aug. 24. The thrift was placed into conservatorship Nov. 20 and would have been put into receivership this week unless the extension was granted.

For months the state has been negotiating with Yorkridge Calvert, a large federally insured Baltimore thrift, to buy First Maryland.

George Nilson, a lawyer representing the state, told Kaplan, "We genuinely believe . . . that we're coming down the stretch with the Yorkridge Calvert transaction. But since Monday, we have encountered a significant obstacle."

Nilson would not elaborate on the snag in the negotiations.