"The local river names and animal names in the Old Rigveda are purely Indo-Aryan names. This phenomenon is noted even by Witzel with surprise: “A better case for the early linguistic and ethnic history of India can be made by investigating the names of rivers. In Europe, river names were found to reflect the languages spoken before the influx of Indo-European speaking populations. They are thus older than c. 4500-2500 B.C. (depending on the date of the spread of Indo-European languages in various parts of Europe).” (WITZEL 1995a:104-105). But, in sharp contrast, “in northern India rivers in general have early Sanskrit names from the Vedic period, and names derived from the daughter languages of Sanskrit later on.[…] This is especially surprising in the area once occupied by the Indus Civilisation where one would have expected the survival of older names, as has been the case in Europe and the Near East. At the least, one would expect a palimpsest, as found in New England with the name of the state of Massachussetts next to the Charles river, formerly called the Massachussetts river, and such new adaptations as Stony Brook, Muddy Creek, Red River, etc., next to the adaptations of Indian names such as the Mississippi and the Missouri”. (WITZEL 1995a:105-107). Blažek (in his paper "Hydronymia Ṛgvedica") shows that out of 29 river-names, 22 have purely Indo-Aryan names, and the rest have suggested Indo-Aryan as well as suggested non-Indo-Aryan alternative etymologies."