1940
plate: 30 x 25.2 cm (11 13/16 x 9 15/16 in.)
Irwin D. Hoffman, gift to Harvard University. Department of Earth and Planetary Sciences, transferred 17 December 1999.
printed in black on heavy white wove paper
20th centuryAmericanEtching with graphite annotations on white, machine wove paper
20th centuryAmericanprinted in black on heavy white wove paper
20th centuryAmerican