Since those remarks were first written, in 1829, a great number of extinct species have been added to our collections of tertiary mammalia from Great Britain and other parts of the world. At length, between the years 1836 and 1839, a few remains of quadrumana were found in France and England, India and Brazil. Those of India, belonging to more than one extinct species of monkey, were first discovered near the Sutlej, in lat. 30° N., in tertiary strata, of which the age is not yet determined; the Brazilian fossil, brought from the basin of the Rio das Velhas, about lat. 18° S., is referable to a form now peculiar in America, allied to the genus Callithrix, the species being extinct. The skull and other bones met with in the South of France belong to a gibbon, or one of the tailless apes, which stand next in the scale of organization to the orang. It occurred at Sansan, about forty miles west of Toulouse, in lat. 43° 40' N., in freshwater strata, probably of the Miocene or middle tertiary period. Lastly, the English quadrumane first met with, occurred in a more ancient stratum than the rest, and at a point more remote from the equator. It belongs to the genus Macacus, is an extinct species, and was found in Suffolk, in lat. 52°,[225] in the London clay, the fossils of which, such as crocodiles, turtles, shells of the genus Nautilus, and many curious fruits, had already led geologists to the conclusion that the climate of that era (the Eocene) was warm and nearly tropical. Some years later (in 1846) the jaw of another British species of fossil monkey, Macacus pliocenus, was announced by Mr. Owen as having been met with in the newer Pleiocene strata, on the banks of the Thames, at Grays, in Essex, accompanying the remains of hippopotamus, elephant, and other quadrupeds, and associated with freshwater and land shells, most of which are now inhabitants of the British Isles.[226] When we consider the small area of the earth's surface hitherto explored geologically, and the new discoveries brought to light daily, even in the environs of great European capitals, we must feel that it would be rash to assume that the Lower Eocene deposits mark the era of the first creation of quadrumana. It would, however, be still more unphilosophical to infer, as some writers have done, from a single extinct species of this family obtained in a latitude far from the tropics, that the Eocene quadrumana did not attain as high a grade of organization as they do in our own times. What would the naturalist know of the apes and orangs now contemporary with man, if our investigations were restricted to such northern latitudes as those where alone the geologist has hitherto found all the fossil quadrumana of Europe?