The skulls from the Roman military station at Newstead proved conclusively that there lived in Scotland during the first century large and small horses with _short-pillared_ molars (fig. 23). This led to the discovery that in Shetland and other ponies of the Celtic type, and in Arabs and thoroughbreds of the Libyan or Siwalik type, some of the molars have as short pillars as in _E. stenonis_ (fig. 21) of the Val d’Arno Pliocene deposits. The investigations of the last decade having indicated that during the Ice Age in Europe, as in America, there were always several species of horses living contemporaneously, an attempt must be made to ascertain from which of the wild prehistoric species Shetland ponies are mainly descended. In addition to steppe horses of the Prjevalsky make and horses allied in skull, teeth, and limbs to _E. sivalensis_ of India, there were in prehistoric times large and small varieties of browsing or forest horses, and “Celtic” and “Libyan” varieties of slender-limbed plateau or desert horses. Although trees and plateaus are conspicuous by their absence in the northern islands, the study of Shetland ponies makes it evident that they have mainly sprung from “forest” and “plateau” ancestors. Evidence of this we have in the limbs and skull as well as in the teeth. A fairly accurate estimate of the type to which a horse belongs, and also of its height, can often be gained from a study of the cannon-bones. For example, in 12-hands ponies of the “Celtic” variety the metacarpals are on an average 200 mm. long and 26·6 mm. wide at the middle of the shaft, whereas in 12-hands ponies of the “forest” type the length is on an average 193 mm. and the width 35 mm.—_i.e._, in the one case the length is 7·5 times the width, in the other only 5·5 times. In Preglacial times there were horses in Umbria with metacarpals 190 mm. by 32 mm., and horses with metacarpals 220 mm. by 30 mm. The 190 mm. metacarpals probably belonged to a long, low, broad-browed 12-hands “forest” pony, while the 220 mm. metacarpals doubtless belonged to a 13-hands fine-limbed pony of the “desert” type. During the Glacial period horses of the “forest” and “desert” as well as of the “steppe” type were common all over Europe.[F16] From the “Elephant-Bed” at Brighton bones of a 12-hands “forest” horse have been recovered. Kent’s Cavern, Torquay, in addition to the bones of a 12-hands “forest” horse, has produced cannon-bones of the same size and width as the fine-boned 13-hands Umbrian pony. [F16] In the vicinity of an open-air settlement to the north of Lyons there are rubbish-heaps said to contain the remains of over 50,000 horses, which served as food during the Solutrian period of the Stone Age.