The Ofnet race seems to have spread westward into the Celtic lands, either at this time or perhaps later, though probably in small numbers, for a skull found at Grenelle, near Paris, under what are believed to be neolithic surroundings, belongs to this type.[64] Other broad-headed skulls of this or the Alpine type, dating from about 5000 /B.C./, or a little earlier, have been found at Mugem on the banks of the Tagus,[65] while others of this type of about the same date have been found in the caves of Furfooz in Belgium.[66] Whether any of this broad-headed Asiatic strain reached the British Isles at so early a date is uncertain. No skulls of this type and date have been discovered, but broad-headed types occur sporadically in Wales, Ireland and the western islands of Scotland, which may conceivably represent descendants of early Ofnet or Alpine immigrants. Somewhat later, before 4000 /B.C./, fresh waves of broad-headed immigrants seem to have arrived in Central Europe from the Armenian highlands or the Anatolian plateau, bringing with them the knowledge of grain, cultivated fruits and domestic animals, and the custom of erecting pile-dwellings in marshes or lakes, and of grinding and polishing axes of flint or other hard stone.[67] Such knowledge seems to have reached even the west of Switzerland by 4000 /B.C./ and to have spread later throughout the _massif central_ of France, which was already peopled by men of the Alpine type. But the art of polishing hard stone spread further than the people who were responsible for its introduction, and during the next few centuries this art had become well known throughout the Celtic lands of the west; the need for more efficient tools to fight the encroaching woodland must have encouraged this art. How far the elements of agriculture had travelled with the art of grinding axes seems uncertain, for few, if any, unquestionable neolithic dwelling sites of this time within this area have been found or thoroughly explored. The scanty evidence at our disposal seems to show, however, that the people of the west were possessed of some domesticated animals, so that the inhabitants of Celtic lands had passed from a purely hunting stage before 3,000 /B.C./ There is one other culture, introduced into Europe perhaps by another race, which I must not omit to mention, as it may have provided another element, albeit a small one, in the early population of Celtic lands. At Mullerup, in the peat moss of Maglemose, in the west of the island of Zealand, there was found in 1900 an important dwelling site with a very distinct culture, including harpoons and other implements of horn and bone, which is known to Scandinavian archæologists as the Mullerup, but to English-speaking students as the Maglemose culture.[68] More recently, in 1917, another settlement, exhibiting what appears to be the same culture, was discovered at Sværdborg, in the south of the same island.[69]