An original working drawing from the construction of one of Wright's best known buildings, the Erik Pratt House in Galesburg, Michigan. Drawing is done in graphite, red pencil and black ink on a 35 x 25 sheet of onionskin paper, and entitled 'Sheet No. 4 Cross Section, House for Mr. and Mrs. Erik Pratt, Galesburg Country Homes.' Signed in the lower right in brown ink on a red square, 'F. LL. W, Mar, 20/49' Matted with a small name plate, to an overall size of 37.5 x 20. In fine condition, with a few trivial spots of toning and soiling. COA John Reznikoff/PSA/DNA and RRAuction COA. Oversized.