We cannot trace the variety of axes characteristic of different times, places, and uses. One, which from its resemblance to a shoemaker's last has been called by the Germans the "_Schuhleistenbeil_," demands mention.[102] This is a heavy, thick, clumsy implement, with one end edged or pointed. The lower surface is flat or slightly concave, the upper nearly semi-circular in cross-section. It reminds us somewhat of the grub-hoe or mattock, and probably served a similar purpose--to break up the ground. It is very common in the loess regions of southeastern Europe, but in the more stony soils of the uplands was generally replaced by a pick made of a stout tine of deer's horn. Broader and flatter hoes are found, and stone ploughshares. We must clearly recognize the distinction between the mattock and a somewhat similar but lighter polished concave axe, with sharp transverse cutting edge, used along the Baltic and elsewhere for hollowing out boats. Adze and mattock are similar in general form, but the carpenter's tool is a much finer instrument than the agricultural implement, and serves a very different purpose. Bone was still used for pointed tools and weapons. A bundle of sharp pointed ribs found at Robenhausen had probably been used for hackling flax, Horn was used for sockets for the smaller chisels, and for a variety of other purposes. Wooden bowls, scoops, and other articles occur among the remains of the lake-dwellings. Flint held much the same place in Neolithic industry as iron or steel with us. Its quality varied greatly in different localities. Our Neolithic ancestors had discovered that it worked better when freshly mined than when long exposed and weathered. Hence a mine of flint of the best quality was as valuable as a field of iron ore or a gold mine to-day. The most celebrated source of flint in France was Grand Pressigny, near Tours, Department of Indre-et-Loire.[103] The color and texture of this flint enables us to recognize it wherever found. It was exported as far as Brittany, Normandy, Belgium, and western Switzerland. At Spiennes, in Belgium, they sunk shafts sometimes to a depth of forty feet. Here horizontal galleries extended out into the layers of chalk containing the best quality of flint. Similar mines were located at Grimes Graves and at Cissbury, in England.[104] The flint was exported sometimes in blocks, sometimes as half or completely finished implements. Around Grand Pressigny workshops are numerous. But they are by no means limited to the immediate vicinity of the mines. In some localities the manufacture was almost limited to one particular article. Here the product was exported in finished form.