SRL for [expended]: Mr. Good , who documents these things as best he can , provides an official explanation in the form of a memorandum from Chief of Staff George C. Marshall to President Roosevelt : `` 1,430 pounds of ammunition , '' he wrote his commander in chief , were [expended] on `` unidentified aircraft , '' flying at speeds as slow as 200 mph and elevations between 9,000 and 18,000 feet .
ARG-1: 1,430 pounds of ammunition | ARG-2: on `` unidentified aircraft , '' flying at speeds as slow as 200 mph and elevations between 9,000 and 18,000 feet