Marketing has begun for the Thorndale Condominium at 406 West 45th Street in Clinton.

This handsome, mid-block building was erected as a carriage house in 1905 for Oakleigh Thorne, the owner of Thorndale Farms in Dutchess County, New York, that had been founded by Isaac and Hannah Thorne in 1725.

It was designed by Frank A. Rooke, who also designed the Claremont Riding Academy on the Upper West Side.

406-408 West 45 Street LLC, of which Jon Greenberg and Thomas Iovane are principals, is the sponsor.

Beyer Blinder Belle is the architectural firm for the conversion of the 6-story, mid-block building into 21 residential condominium apartments.

Floors 2 through 5 will have four apartments each and there are also two penthouses, each with indoor and outdoor fireplaces.

Apartments will have brick walls and beamed ceilings and most will have gas fireplaces.

The building, which is located between 9th and Tenth Avenues, has a one-story rusticated limestone base, a bicycle room and private storage.

The attended lobby have a 12-foot ceiling, wood paneling and refrigerated storage for perishable deliveries.

Kitchens will have Viking 30-inch sealed burner gas ranges, SubZero refrigerators and wine coolers, Icestone glass and pearl composite countertops and backsplashes, and white- lacquer-and-aluminum-edge cabinetry.

Bathrooms will have Starck 3 tubs, Villeroy & Boch ceramic sinks with Dornbracht fixtures.

Prices range from about $600,000 for a 681-square-foot one-bedroom, one-bath apartment on the second floor to about $1,675,000 for a two-bedroom, two-bath penthouse with 1,059 square feet of interior space and 1,251 square feet of terrace.

Two-bedroom, two-bath apartments with 1,274 square feet are priced at about $1,250,000 and have living/dining areas that 34 feet 2 inches long.

Apartment ceilings range in height from 10 to 14 feet.

There is excellent cross-town bus transportation on 42nd Street and this neighborhood is convenient to the Theater District.