The supports of the large and handsome dolmen of the little island of Gavrinis, Morbihan, are filled with engraved lines running into one another and conforming to the shape of the stone or to its composition--all the siliceous and consequently very hard parts being free from them. This indicates a simple ornamentation or decoration executed without any special plan made in advance, according to the nature and form of the stone worked upon. Yet, among the lines of the apparently fanciful ornament a number of polished stone hatchets are very distinctly represented. In all the other dolmens the carvings are much less numerous and not so close. Sometimes they are distributed around, and sometimes they are isolated. Among them we remark the frequent repetition of some forms in groups or singly, which suggest the thought of signs with a determined sense. Upon a large support of the dolmen of the Petit-Mont at Arzan (Morbihan) there are at the lower left hand three crosses, a sign of frequent occurrence on the megalithic carvings. Above these are two very wide open U's. Seidler sees in these signs letters of the Libyan alphabet, the cross corresponding to C, and the other sign to M. Some persons have further thought they could distinguish an Egyptian letter in the cross. Taking a more general view of the question, Letourneau[34] has tried to prove that the sculptures on the megaliths are inscriptions, and the engraved signs correspond to letters of the ancient alphabets, most probably Semitic. Adrien de Mortillet answered that the thought of writing involved arrangement, and no arrangement could be predicated of the signs.