Alexander Von Humboldt, who in the year 1800 came across from Venezuela to Cuba to study the flora, fauna and natural resources of the Island, mentioned what he called the petroleum wells of the Guanabacoa Ridge, located not far from Havana, at a point once known as the mineral springs of Santa Rita. Richard Cowling Taylor and Thomas C. Clemson, in a book published in 1837, mentioned “the petroleum wells of Guanabacoa” which had been known for three centuries and that were undoubtedly the wells to which Baron Von Humboldt had previously referred. La Sagra, too, in 1828, described petroleum fields located near Havana, and in 1829, Joaquin Navarro described several deposits of bituminous material in a report which he made to the “Real Sociedad Patriotica.” The bituminous deposits referred to by Taylor and Clemson proved to be a solid form of asphalt. It was afterward used in large quantities as a substitute for coal. They speak of finding crude petroleum also, filling the cavities in masses of chalcedony, only a few yards distant from the asphalt. The place referred to was afterwards ceded to the mining companies of Huatey and San Carlos, located twelve miles from Havana, where may still be seen the original wells. In a report on bituminous products of the Island by G. C. Moisant, reference is made to a liquid asphalt or petroleum found in Madruga, a small town southeast of Havana. This petroleum product, according to recent investigations, flows from cavities in the serpentine rocks found near Madruga and surrounding towns. An oil claim was registered in 1867 near Las Minas, 18 kilometers east of Havana, as the result of oil indications in the cavities of rocks that cropped out on the surface. A well was opened that yielded some oil at a depth of 61 meters. This was sunk later to 129 meters but afterwards abandoned. Within the last few years several wells have been drilled in the vicinity of the old Santiago claim and have produced a considerable amount of oil. The General Inspector of Mines, Pedro Salterain, in 1880 reported the presence of liquid asphalt, or a low grade of crude petroleum, that flowed from a serpentine dyke, cropping out on the old Tomasita Plantation near Banes, on the north coast some twenty miles west of Havana. The product was used for lighting the estate. All of the wells of this province are located on lands designated by geologists as belonging to the cretaceous period. This is true of those properties where indications of petroleum are found near Sabanilla de la Palma and La Guanillas, in the Province of Matanzas.