388 Karl Pettersen — Geology of N. Norway. 



Intercalated beds of a greenish actinolite slate are observed in 

 various places. In Tromso there are layers of an eclogitic rock alter- 

 nating with the mica-slate; and along the Gullesfjord at Hindo of 

 garnet rock alternating with coarse granular limestone. Alum- 

 slate is frequently found in the mica- slate section. 



The direction of the strike in this section agrees approximately 

 with that observed in the gneiss section. The dip may be partly 

 east and partly west. Through a profile line in an easterly direction 

 from the coast to the boundary of the realm, there occur as many as 

 four deviations in the direction of the dip. 



As accessory elements there may be remarked : 



1) In the proper mica-slate : — red garnets, with which the rock is often abun- 

 dantly sprinkled; blue disthene, staurolite, pistazite,titanite and magnetite, which 

 last mineral may in some places appear in the slate in such abundance as to 

 form an esential element in place of the mica. 



2) In the coarse granular limestone: — mica, quartz, pyrites., graphite, the last 

 mineral often abundantly mixed with the stone in small leaves and stripes ; also 

 tremolite, often in fine broad bar-like aggregations ; felspar and scapolite. 



3) In the green amphibolitic actinolite slate : — yellow epidote. 



4) In the amphibolitic partly eclogitic rock :— black hornblende, inlaid like por- 

 phyry, magnetite, quartz, titanite, tourmaline, pistazite, garnet, calcareous spar, 

 scapolite, apatite and oligoclase (with twin striation). 



In a quartz vein which traverses the mica-slate there has been 

 found reddish fluor-spar. Layers of the Fahlband character are 

 found in some places sprinkled with copper pyrites. The thickness 

 of the group reaches up to 1900 metres. Petrifactions have not 

 hitherto been observed. The age is consequently undecided. Probably 

 it is old Cambrian (perhaps analogous to the Huronian formation). 



III. — The slate-field of Balsfjord occurs in large connected tracts 

 in the interior of the Amt of Tromso, and further in some of the 

 islands of the coast tract, viz. Eingvateo and Hindo. The group is 

 formed of a series of layers of argillaceous slate, argillaceous mica- 

 slate, shining slate, and hard slate. Among these there are found 

 thick inlay ings of a limestone, which is partly coarse-grained and 

 greyish, partly bluish-black and carboniferous, and often rather fine 

 grained. Alum-slate also occurs frequently between the layers of the 

 slate group. 



The limestone often contains much magnesia (magnesian lime- 

 stone). The latter often contains magnetic iron, which also appears 

 in more connected vein-like masses. In the quartz-layers connected 

 with the group there are found in some places, in drusy cavities, 

 very beautiful rock crystals. 



Argentiferous galena occurring in lumps in layers of quartz and 

 limestone is found in one place, namely, the mountain district of 

 Eubben at Bardo. 



With the Group II., as also with the Group III., there are con- 

 nected frequent layers of soap-stone, in which may be found both 

 Bitterspar and pyrites. 



The direction of the strike in this group is predominantly 60° to 

 70°, the dip northerly, usually slight and seldom over 30°. Petri- 

 factions have not been observed in this group. The age is, conse- 

 quently, undecided — probably younger Cambrian (may possibly be 



