Although the shapes of these stone implements are very varied, they may all be classed under a certain number of prevailing types; and these types are to be found in very different countries. The flint hatchets are at first very simple although irregular in their shape; but they gradually manifest a much larger amount of talent exhibited in their manufacture, and a better judgment is shown in adapting them to the special uses for which they were intended. The progress of the human intellect is written in ineffaceable characters on these tablets of stone, which, defended as they were, by a thick layer of earth, bid defiance to the injuries of time. Let us not despise these first and feeble efforts of our primitive forefathers, for they mark the date of the starting-point of manufactures and the arts. If the men of the stone age had not persevered in their efforts, we, their descendants, should never have possessed either our palaces or our masterpieces of painting and sculpture. As Boucher de Perthes says, "The first man who struck one pebble against another to make some requisite alteration in its form, gave the first blow of the chisel which has resulted in producing the Minerva and all the sculpture of the Parthenon." Archæologists who have devoted their energies to investigating the earliest monuments of human industry, have found it necessary to be on their guard against certain errors, or rather wilful deceptions, which might readily pervert their judgment and deprive their discoveries of all character of authenticity. There is, in fact, a certain class of persons engaged in a deceptive manufacture who have taken a delight in misleading archæologists by fabricating apocryphal flint and stone implements, in which they drive a rather lucrative trade. They assert, without the least scruple, the high antiquity of their productions, which they sell either to inexperienced amateurs, who are pleased to put them in their collections duly labelled and ticketed, or--which is a more serious matter--to workmen who are engaged in making excavations in fossiliferous beds. These workmen hide the fictitious specimens in the soil they are digging, using every requisite precaution so as to have the opportunity of subsequently extracting them and fingering a reward for them from some too trusting naturalist. These imitations are, moreover, so cleverly made, that it sometimes requires well-practised eyes to recognise them; but they may be recognised with some degree of facility by the following characteristics:-- [Illustration: Fig. 8.--_Dendrites_ or Crystallisations found on the surface of wrought Flints.]