The Swiss archæologist mentioned above by Prof. Douglas is Fritz Roediger (_a_), of whose theory the following is a translated abstract:
What renders the deciphering of these sign stones exceedingly difficult (I purposely avoid the words “map stones” because not all are such) is their great variety in size, position, material, workmanship, and meaning. I will here speak of the latter only, inasmuch as there are stones which in their smallest and their largest form are yet frequently nothing else than boundary stones, whose origin can often not be definitely established as prehistoric, while on the other hand again we discover well-marked boundary stones, which at the same time show the outline of the piece of ground which they guard. Similarly we find prehistoric (Gallic) “Leuk” stones, differing from the meter-high communal and state boundary stones of modern times in nothing but this, that they have some indistinct grooves and one or two hooks, while on the other hand we meet “Leuk” stones, which on their restricted heads, often also on the side walls, indicate their environs for (Leuk) miles around, up, down, and sidewise, while a third class of this form merely adorn crossroads, and indicate deviations by means of lines and points (waranden). Thus we find quite extensive slabs or structures that signify only some hectares, often only one, while we meet very small ones, or, at any rate, of moderate size, which, one man can move, that represent very large districts, some presenting only lines and grooves, others with shells of various sizes, a third kind with both kinds of ornaments and samples of ornaments, and again others with no sign at all, but yet respected as stones of special meaning by the population, and called “hot stone,” “pointed stone,” “heath stone,” “child’s stone,” etc. Other stones have basin-like or platter-like depressions, and finally there are outcropping rocks with marks of one kind or another, holes, rents, clefts, etc. A further great difficulty hampering the deciphering of these wonderful stones is the lack of opportunities for comparison and experience. I have been markedly favored in this respect by my sojourn and wanderings in valley, mountain and alp. Western Switzerland is a very paradise for investigations of this kind, especially the lake country and the upper part of the canton of Solothurn (Soleure). A third difficulty, often insuperable, lies in the nonexistence of appropriate good maps for comparison. In this respect too we are well off in Switzerland.