WATHEN SCHOOL INC. to ST. CLARE'S HOSPITAL in the principal sum of $575,000.00 and recorded in Liber 6038 of Mortgages, Page 220, in the office of tho City Register of the County of New York on March 13, 1962, which mortgage was thereafter ASSIGNED by an Assignment of Mortgage dated June 9, 1975 by ST. CLARE'