Montgomery County took steps yesterday to examine the financial records of the Greater Laytonsville Civic Association in an attempt to find out who has contributed to the group as well as requesting details on a New York consulting firm hired by the group to stop a county landfill.

A summons for a deposition, which was delivered to Donald McComb, the civic association's executive director, was the latest development in a county Circuit Court case brought by six Laytonsville citizens against 14 current and former county officials, including County Executive Charles W. Gilchrist and members of the County Council.

The suit, filed in February 1981, seeks to stop the landfill from opening in June, asks for $21 million spent on the project to be returned to the county's treasury, and declares that the landfill violates county law because it is in a residential area.

The court has ruled that the law is invalid. The issue is now before the Maryland Court of Appeals.

Ray Schoenke, president of the Laytonsville citizens' group, told the County Council yesterday that he was "outraged" at the summons and called it "a flagrant abuse of governmental power. . . . "

The summons asks McCombs for all financial records of the association, including those dealing with contributions. The summons also asks McCombs for all information regarding a national firm recently hired by the group to prove that the present design of the landfill is unsafe.

Albert D. Brault, a Rockville attorney hired by county officials in the case, said the summons was "routine" and had no further comment. Schoenke said his group would fight the summons.