50 COGGIN BROWN : MINES & MINERAL RBSOURGBS OF YUNNAN. 



blende schists and a white porphyritic granite. Further 

 south, where the great range begins to die down, the 

 granites are developed at the expense of the other crys- 

 talline rocks, which are normally fine-grained biotite 

 schists and white augen gneisses. Two varieties of 

 granite occur there, the first, a coarse-grained, gneissose 

 kind and the second, a finer sort in thin veins, evidently 

 of later age. 

 (b) The Tsang Shan complex.— The T'sang Shan range is a 

 high mountain wall rising to elevations of 13,(100 feet 

 on the western shores of lake Euh Hai, near Ta-li Fu. 

 Gneisses, schists and crystalline limestones all have a 

 part in its structure and they are intruded by a gneissose 

 granite. The band is not a wide one in this region and 

 its northern limits is not known. (Loczy indicates a 

 small granite boss near Li-chiang Fu, and part of a 

 larger intrusion to the north-east of Wei-hsi T'ing.) 



(6) The Shun-ti ing- Yun-chou-Mien-ning crystalline series. — The 

 crystalline rocks around these towns appear to form 

 part of one band which is in much the same line of 

 strike as the T'sang-shan band, though not directly 

 connected with it on the surface. Around Shun-ning 

 Fu gneisses, schists and granite occur, the former ex- 

 tending for some 10 miles towards the north, almost 

 up to the Mekong. Muscovite and biotite granites 

 were both seen, but the former is commoner. Mica 

 schists, quartz schists and various forms of gneisses 

 occur between Shun-ning Fu and Yun-chou, and also 

 near Mien-ning T'ing where the band id 15 miles wide 

 from east to west. 



(d) The Yang-tze series. — Crystalline rocks occur in the Yang- 

 tze valley in the vicinity of its confluence with the Yalung. 

 Specimens from this region were collected by Leclere 

 and examined by Levy and Lacroix who determined 

 them as diorites with bytownite, passing into amphi- 

 bolites. The diorite is traversed by veins of micro- 

 granulite containing amphibole, black mica, oligoclase 

 and pyrite. In the region of the Ya-lung there is a great 

 massif made up of granulite which near Hui-li Chou 

 is traversed by thick dykes of an a)girine-bcaring 



