Research subject. The clayey rocks of the Vendian Serebryanka and Sylvitsa groups on the western slope of the Middle Urals.Material and methods. The research materials comprised data on the content of main rock-forming oxides in clayey rocks (mudstones, shales, fine-grained clayey siltstones, ≈180 samples in total) with the values of losses on ignition <6 wt %. This information, obtained at the beginning of 2000 by the X-ray fluorescence method at the Institute of Geology and Geochemistry, Ural Branch of RAS, was used to calculate the average, minimum and maximum values of various weathering indices. Samples were taken from natural outcrops in the basins of the Chusovaya, Serebryanka, Sylvitsa, Mezhevaya Utka, Usva and Koiva rivers.Results. It was established that the sedimentary sequences of the Serebryanka and Sylvitsa groups, in which diamictites are present at several levels, do not exhibit a noticeable contrast in the values of various chemical indices of weathering. For example, taking into account the values of standard deviations (±1σ), the values of the Ruxton coefficient for all nine Vendian formations are statistically comparable. The same is characteristic of the average values of CIA, CIW, PIA, ICV and MIA(o) for clayey rocks of different formations. Variations in the average CPA values show that, taking into account ±1σ, only the rocks of the Starye Pechi, Garevka and Perevalok formations can be considered statistically different. Taking into account ±1σ, the clayey rocks of the Buton Formation differ significantly from the fine-grained clastic rocks of the Garevka and Kernos formations in terms of the average value of the Mg-index. The clayey rocks of the Tanin and Kernos formations have a weak or moderate positive correlation between the TiO2/Al2O3 ratio and the Ruxton, PIA, ICV indices and the hydrolyzate modulus. This suggests the dependence of the listed indicators of the intensity of weathering from the composition of rocks in paleocatchments.Conclusions. The data obtained suggest that, when averaging at the level of formations (even if the formations include quite a lot of undoubtedly glaciogenic deposits), we apparently do not record the specific contribution of the latter and, as a result, we obtain a substantially different picture than that which emerges for other Neoproterozoic deposits, including diamictites, varved clays, and intervals with dropstone.