The science of geology entered the future Eritrean region through the observations and publications of two German explorers, Christian Ehrenberg (1820s) and Eduard Rüppel (1830s). Areal geological mapping followed surprisingly soon thereafter, a three-year survey (1839-42) pioneered by two French lieutenant military engineers, Adolphe Ferret and Joseph Galinier. Their 1:1 million map outlined the basic stratigraphy of the plateau in southern Eritrea and northern Ethiopia. Down in the warmth of sub-sea level Afar, Werner Münzinger mapped the evaporitic sequence of the Salt Plain when extending his Ottoman, and later British, consular duties (1860-75). During the same period, explorer Theodor von Heuglin scrutinised the basement terrain of highland Eritrea. In 1867, careful traverse mapping by William Blanford, attached to the British military expedition sent from India to confront Ethiopian Emperor Tewodros, resulted in a book on the geology and stratigraphy of the Eritrea-Wallo plateau margin, illustrated with a 1:875,000 map (1870). The establishment of the Italian colony of Eritrea in 1890 immediately spurred the mapping of its geology, accomplished by Luigi Baldacci who was London-trained and well practised from a four-year survey of the entire island of Sicily. In addition to a fine 1:400,000 geological map (1891), Baldacci initiated the practice, followed by field geologists such as Giotto Dainelli, Pietro Verri and Aldo Bibolini, of sending field samples back to Italian laboratories for some excellent mineral and rock analyses. The unexpected geology of the Red Sea hills (Dancalia) was revealed and mapped through a camel-supported survey by Paolo Vinassa de Regny (1919-20), his rock samples analysed by Maria de Angelis in Milano. During the 1930s, the Neogene sediments of coastal Eritrea were being mapped by renowned petroleum geologist Cesare Porro, while on the plateau detailed lithologic and structural mappings of areas of metamorphic basement were initiated by Antonino Francaviglia and also Ciro Andreatta. Mussolini’s invasion of Ethiopia in 1935 ended all that.