On the other hand, the decided majority of its radicals have no affinity with Kechua, and betray a preponderating influence of some other stock. What this may have been must be left for future investigation. It does not seem to have been the Puquina; for although that tongue borrowed from both the Aymara and the pure Kechua dialects, its numerals indicate a stock radically apart from either of them. The Aymara was spoken with the greatest purity and precision by the Pacasas; and next to these, by the Lupacas; and it was especially on these two dialects that Bertonio founded his Grammar, and not upon the mongrel dialect of the imported laborers, as Markham would have us believe.[308] The physical traits of the Aymara Indians offer some peculiarities. These consist mainly in an unusual length of the trunk in proportion to the height, in a surprising development of the chest, and short extremities. The proportion of the thigh to the leg in length is under the average. The leg and calf are well developed, and the general muscular force good. The hands and feet are smaller even than is common in the American race. The skull has a tendency to dolichocephaly.[309] The unusual thoracic development is plainly attributable to the tenuity of the atmosphere breathed by these residents of heights varying from 4,000 to 17,000 feet above sea level. Making allowances for the results of this exposure, they do not differ materially from the general physical habits of the Kechuas. The location they occupied was generally to the south and east of the Kechuas, upon the plateau and western slopes of the Andes, from south latitude 15° to 20°, and through about six degrees of longitude. It may be said roughly to have been three hundred miles from north to south, and four hundred from east to west. The total native population of this area to-day is about six hundred thousand, two-thirds of whom are of pure blood, and the remainder mixed. Some of them dwell along the sea coast, but the majority are on the Bolivian plateau, the average altitude of which is more than twelve thousand feet above sea level. The old writers furnish us very little information about the Aymaras. At the time of the discovery they were subject to the Kechuas and had long been thus dependent. Many, however, believe that they were the creators or inspirers of the civilization which the Kechuas extended so widely over the western coast. Certain it is that the traditions of the latter relate that their first king and the founder of their higher culture, Manco Capac, journeyed northward from his home on the shores of Lake Titicaca, which was situated in Aymara territory. From the white foam of this inland sea rose the Kechua culture-hero Viracocha, who brought them the knowledge of useful arts and the mysteries of their cult.