Before proceeding to acquaint our readers with the facts brought to light by the Danish commission, it will be well to remark that Denmark does not stand alone in possessing these kitchen-middens. They have been discovered in England--in Cornwall and Devonshire--in Scotland, and even in France, near Hyères (Bouches-du-Rhône).[18] MM. Sauvage and Hamy have pointed out to M. de Mortillet the existence of deposits of this kind in the Pas-de-Calais. They may be noticed, say these naturalists, at La Salle (Commune of Outreau) at certain parts of the coast of Portel, and especially a very large heap at Cronquelets (Commune of Etaples.) They chiefly consist of the _cardium edule_, which appear to abound in the kitchen-middens of the Pas-de-Calais. Messrs. Evans, Prestwich, and Lubbock observed one of these deposits at Saint-Valery, near the mouth of the Somme. Added to this, they have been described by various travellers as existing in different parts of the world. Dampier studied them in Australia, and Darwin in Tierra del Fuego, where deposits of the same character are now in the course of formation. M. Pereira da Costa found one on the coast of Portugal; Sir C. Lyell has testified to the existence of others on the coasts of Massachusetts and Georgia, in the United States; M. Strobel, on the coasts of Brazil. But those in Denmark are the only deposits of this kind which have been the subject of investigations of a deliberate and serious character. Almost all these kitchen-middens are found on the coast, along the _fiords_, where the action of the waves is not much felt. Some have, however, been found several miles inland; but this must be owing to the fact that the sea once occupied these localities, from which it has subsequently retired. They are not to be met with on some of the Danish coasts, as those of the western side; this, on the one hand, may be caused by their having been washed away by the sea, which has there encroached on the land, or, on the other hand, by the fact that the western coast was much less sheltered than the other parts of the Danish peninsula. They are not unfrequently to be found in the adjacent islands. These kitchen-middens form, in a general way, undulating mounds, which sink in a gentle incline from the centre to the circumference. The spot where they are thickest indicates the site of the habitations of man. Sometimes, we may notice one principal hillock, surrounded by smaller mounds; or else, in the middle of the heaps, there is a spot which must have been the site of the encampment. These refuse deposits are almost entirely made up of shells of various kinds of molluscs; the principal species are the oyster, the cockle, the mussel, and the periwinkle. Others, such as whelks, _helices_ (edible snails), _nassa_, and _trigonella_, are also found; but they are comparatively few in number.