It is unfortunate that, owing probably to the character of the country, remains of the Stone Age in Babylonia are wanting so that no comparison can yet be made with the neolithic cultures of Egypt and the Aegean. The constant floods to which Babylonia was ever subject swept away all traces of early occupations until the advent of the Sumerians, who built their cities on artificial mounds. The question of Akkado-Sumerian[586] origins is by no means clear, for many important cities are unexplored and even unidentified, but the general trend of recent opinion may be noted. The linguistic problem is peculiarly complicated by the fact that almost all the Sumerian texts show evidence of Semitic influence, and consist to a great extent of religious hymns and incantations which often appear to be merely translations of Semitic ideas turned by Semitic priests into the formal religious Sumerian language. J. Halevy, indeed, followed by others, regarded Sumerian as no true language, but merely a priestly system of cryptography[587], based on Semitic. As regards linguistic affinities, K. A. Hermann[588] endeavoured to establish a connection between the early texts and Ural-Altaic, more especially with Ugro-Finnish. A more recent suggestion that the language is of Indo-European origin and structure rests on equally slight resemblances. The comparison with Chinese has already been noticed. J. D. Prince[589] utters a word of caution against comparing ancient texts with idioms of more recent peoples of Western Asia, in spite of many tempting resemblances, and claims that until further light has been shed on the problem Sumerian should be regarded as standing quite alone, "a prehistoric philological remnant."