Source: P. Lowell:  New observations of the planet Mercury. 

Cambridge, J. Wilson and son, 1902. In Memoirs of the American academy of arts and sciences, n.8., v.12, no.4

The book also includes tens of drawings of Mercury.

According to the author, the planet is “covered with long narrow markings best explained as the result of cooling”, and Mercury “is a world as dead as the Moon, but differently brought to that condition”. The map shows an elliptical view because Lowell thought that Mercury is “an ellipsoid”.