For the proper understanding of what is to follow the distinctions just pointed out should always be borne in mind, as none are more important. Half indeed of the confusion that exists on the subject arises from their having been hitherto neglected. There is no doubt that occasional similarities can be detected between these various styles, but they amount to nothing more than should be expected from family likenesses consequent upon their having a common origin and analogous purposes. But, except to this extent, these styles seem absolutely distinct throughout their whole course, though running parallel to one another during the whole period in which they are practised. If this is so, any hypothesis based on the idea that the microlithic architecture either preceded or succeeded to the megalithic at once falls to the ground. Nor, if these distinctions are maintained, will it any longer be possible to determine any dates in succession in megalithic art from analogies drawn from what may have happened at any period or place among the builders of microlithic structures. The fact which we have got to deal with seems to be that the megalithic rude stone art of our forefathers is a thing by itself--a peculiar form of art arising either from its being adopted by a peculiar race or peculiar group of races among mankind, or from its having been practised by people at a certain stage of civilization, or under peculiar circumstances, and this it is our business to try to find out and define. But to do this, the first thing that seems requisite is to put aside all previously conceived notions on the subject, and to treat it as one entirely new, and as depending for its elucidation wholly on what can be gathered from its own form and its own utterances, however indistinct they may at first appear to be.