But even in those cases where there is some approach to the plan of the old diagram, Mr. Adams found that it was clearly not due to any scheme for constructing a baffling system of bolt-runs for defensive purposes, but purely incidental to the work of excavating the nest cavity and getting rid of the material dug out. The easiest way to dispose of this redundant earth is to push it to the surface, and to do this a tunnel has to be made above the nest cavity. This, as a rule, is originally only from two to six inches below the surface, but the hoisting out of the surplus earth causes the formation of a solid dome of considerable thickness above it. The tunnels thus made to get rid of earth usually end in blind terminals, and would not be available for escape in the case, say, of the "fortress" being entered by a Weasel. It is notable that in the only one of Mr. Adams' plans that approaches nearly to the old figure there is no connection between the "galleries" and the nest cavity. In some soils (like the Bunter Sandstone) Adams found that stones of four ounces are turned out--that is, equal to the average weight of an adult Mole. He also found that "the softer the soil, as a rule, the nearer are the runs to the surface." In his work "De la Taupe," de Vaux says: "The Mole places his habitation in the most favourable spot in his cantonment; he studies everything, and never does he make a mistake except under circumstances which he has been unable to foresee, such as continuance of rains, a flood; then he makes up his mind promptly, and establishes himself elsewhere. It is by preference that he places his fortress in the foundation of a wall, under a hedge, at the foot of a tree." [Illustration: _Pl. 6._ _C 18._ *Mole making a new burrow.* When alarmed above ground it dives rapidly into soft earth.] [Illustration: _Pl. 7._ _C 19._ *In the Mole's Nursery.* The young have wrinkled pink skin.] Upon this Adams has the following comment:-- "With regard to a deliberate choice of 'the most favourable spot' after a survey of the cantonment by a practically blind animal of the Mole's impatient disposition and subterranean habits, there can be no question as to its absurdity."