418 PROCEEDINGS OF THE ACADEMY OF [1897. 



were examined and the return to the railway was made at the 

 station Souleia over Devonic measures. 



From Souleia to Slatooust the upper divison of lower Devonic 

 D* is passed over as well as Dj. Near the station Berdiaouch the 

 dolomites D| are seen with thick dykes of porphyroid granite 

 intercalated among them and resembling the Finland Rappakiwi. 

 Between Berdiaouch and Toundouch the line pursues the horizon 

 of the Devonic limestones and dolomites, showing frequently the 

 foliated structure below described. 



Finally a complex succession of rocks begins at the village of 

 Medwediova containing limestones, schists and argillaceous and 

 sericitic sandstones, mica schists, diabases, araphibolites and gneiss, 

 all thrown into folds of high dip and penetrated by faults. The 

 mutual relations of the massive rocks, crystalline schists and the 

 quartzites of Ourenga and Kossotour are clearly seen in the sections 

 near Slatooust. This town lies in a picturesque valley of the river Ai. 

 The Kossotour and Ourenga heights which border it, on the north 

 and south respectively are similarly composed and are parts of the 

 same orographic unit. 



Under the leadership of Mr. Tscherneschew, Kossotour was 

 reached by a brisk walk through the woods from the station of 

 Slatooust and sections were made along the river Ai, showing coarse 

 grained mica schists and amphibulite, containing large Garnets, 

 diabase, garnetiferous mica schists, diabase, mica schists, massive 

 diabase containing an abundance of secondary products and strongly 

 altered, mica schist of Biotite, Muscovite, Quartz, and Epidotes, 

 enclosing large Garnets; diabase, mica schists with Almandine; 

 amphibolite more or less schistose, and mica schists with small 

 garnets. 



A section in the railway cut near the station from southwest to 

 northeast, showed a series of mica schists dipping ± southeast — 65°. 

 There are many inclusions of milk quartz and the bedding becomes 

 thicker to the north-east, after the first 100 ft., but the general 

 character of the rocks is comparatively uniform and resembles that 

 of some American rocks, called by the late Dr. Hunt "Taconic." 

 About 200 ft. from the commencement of the section is a mass 

 of quartzite and further to the north-east again mica schists, 

 followed by garnetiferous schist, the Garnets being large and 

 round. To these succeed more mica schists, intercalated among 

 which appeared other small outcrops of quartzite. The railway 



