BALTIMORE -- Arundel Corp., a Baltimore-based producer and marketer of construction materials, announced last week that it has agreed to be acquired for $85 million by Florida Rock Industries Corp. of Jacksonville, Fla.

The acquisition, for $40 a share, should be completed by late January, pending shareholder and governmental approval, the company said.

Florida Rock, a construction materials company, reached the agreement with executives and shareholders of Arundel who control 53 percent of the company's 2.1 million outstanding shares.

Charlotte Waters, corporate secretary for Arundel, a construction materials and real estate development firm said the agreement grants Florida Rock a purchase option and proxies representing 53 percent of the company's outstanding stock.

Arundel's 900 employes will not be affected by the transaction, a company spokesman said. About 500 of those employes are in Maryland.

For the nine months ended Sept. 30, Arundel earned $5.76 million on sales of $69.81 million, Waters said. By comparison, Florida Rock posted earnings of $14.3 million on sales of $200 million for the nine months ended June 30.

In addition to construction materials, Arundel, which was incorporated in 1919, also is involved in the acquisition, development and sale of real estate.

The company has 12 industrial facilities and one office in Maryland. Outside Maryland, it operates 14 plants in four states.

Florida Rock mines, processes and sells construction aggregates in Florida and Georgia. It produces concrete materials in Florida, southern Georgia, Northern Virginia and Washington.