There was never any consensus among the proponents of the concept the existence of a "Caucasoid race" with regard to how it would be delineated from other proposed groups such as the proposed Mongoloid race. Coon (1939) included the populations native to all of Central and Northern Asia, including the Ainu people, under the Caucasoid label.
For example, Thomas Henry Huxley (1870) classified all populations of Asian nations as Mongoloid.
Lothrop Stoddard (1920) in turn classified as "brown" most of the populations of the Middle East, North Africa, the Horn of Africa, Central Asia and South Asia.
He counted as "white" only European peoples and their descendants, as well as a few populations in areas adjacent to or opposite southern Europe, in parts of Anatolia and parts of the Rif and Atlas mountains.
In 1939 Coon argued that the Caucasian race had originated through admixture between Homo neanderthalensis and Homo sapiens of the "Mediterranean type" which he considered to be distinct from Caucasians, rather than a subtype of it as others had done.
Caucasian variety – I have taken the name of this variety from Mount Caucasus, both because its neighborhood, and especially its southern slope, produces the most beautiful race of men, I mean the Georgian; and because all physiological reasons converge to this, that in that region, if anywhere, it seems we ought with the greatest probability to place the autochthones (original members) of mankind.
In contrast to Meiners, however, Blumenbach was a monogenist – he considered all humans to have a shared origin and to be a single species.
While Blumenbach had erroneously thought that light skin color was ancestral to all humans and the dark skin of southern populations was due to sun, Coon thought that Caucasians had lost their original pigmentation as they moved North.
In 1962, Coon published The Origin of Races, wherein he proposed a polygenist view, that human races had evolved separately from local varieties of Homo erectus.
Caucasoid traits were recognised as: thin nasal aperture ("nose narrow"), a small mouth, facial angle of 100°–90°, and orthognathism, exemplified by what Blumenbach saw in most ancient Greek crania and statues.