Regional geographical terminology and its role in onomastic researches

The paper presents a brief overview of researches in geographical terminology of the Northern-Russian dialects and languages as substrata and adstrata for the Northern-Russian dialects. The main problems of studying of the geographical appellative lexicon in areal linguistics and in historical prospects are regarded. The author analyses the work «The Dictionary of geographical terms in Russian speech of Perm Krai» (Perm, 2007) by Prof. E.N.Polyakova; the author of the article emphasizes remarkable utility of this dictionary and its data for researches in the field of historical lexicology of Russian, lexicology of Russian dialects and onomastics.