File:The Quarterly journal of the Geological Society of London (13936980211).jpg

90

 PROF. 
 T. 
 G. 
 BONNET 
 ON 
 TWO 
 TEA 
 VERSES 
 OF 
 THE 
 

the

 range. 
 These 
 rocks 
 have 
 a 
 marked 
 resemblance 
 to 
 the 
 " 
 Lepon- 
 

tine

 gneiss 
 " 
 of 
 the 
 Central 
 Alps. 
 I 
 wrote 
 in 
 my 
 diary 
 : 
 — 
 " 
 The 
 

rocks

 seen 
 at 
 the 
 head 
 of 
 the 
 Gschlossthal 
 vary 
 in 
 aspect 
 from 
 the 
 

i

 Antigorio 
 ' 
 gneiss 
 through 
 the 
 Monte 
 Leone 
 gneiss 
 to 
 that 
 of 
 the 
 

pass

 of 
 St. 
 Gothard, 
 but 
 I 
 have 
 seen 
 nothing 
 which 
 resembles 
 the 
 

Tremola

 schists." 
 

The

 strong-banded, 
 micaceous 
 and 
 hornblendic 
 gneisses 
 mentioned 
 

above

 are 
 traversed 
 on 
 the 
 ascent 
 to 
 the 
 Yelber-Tauern 
 pass. 
 My 
 

observations

 of 
 the 
 foliation, 
 which 
 is 
 often 
 associated 
 with 
 mineral 
 

banding,

 give 
 strikes 
 varying 
 from 
 E.N.E. 
 to 
 E.S.E., 
 with 
 a 
 moderate 
 

dip,

 say 
 about 
 25°, 
 on 
 the 
 southern 
 side 
 ; 
 but 
 there 
 are 
 frequent 
 

indications

 of 
 rolling 
 and 
 twisting, 
 for 
 higher 
 up 
 the 
 dips 
 vary 
 from 
 

the

 southern 
 to 
 the 
 northern 
 side, 
 and 
 north-westerly 
 strikes 
 seem 
 

to

 predominate. 
 As 
 we 
 approach 
 the 
 crest 
 of 
 the 
 pass 
 the 
 beds 
 are 
 

more

 coarsely 
 crystalline 
 and 
 may 
 be 
 true 
 granites 
 ; 
 they 
 show 
 a 
 

certain

 foliation, 
 but 
 not 
 mineral 
 banding. 
 On 
 the 
 upper 
 part 
 of 
 the 
 

descent

 towards 
 the 
 north 
 we 
 meet 
 with 
 a 
 considerable 
 amount 
 of 
 

hornblendic

 rock 
 (HornblendescMefer, 
 V. 
 II.), 
 sometimes 
 dark, 
 some- 
 

times

 spotted 
 with 
 white 
 felspar 
 (?), 
 occasionally 
 rather 
 coarse, 
 

slightly

 foliated 
 or 
 now 
 and 
 then 
 even 
 banded, 
 varying 
 from 
 massive 
 

to

 rather 
 platy 
 in 
 structure, 
 on 
 the 
 whole 
 very 
 like 
 some 
 of 
 the 
 horn- 
 

blende-rock

 in 
 the 
 Hebridean 
 series. 
 Very 
 much, 
 if 
 not 
 all, 
 may 
 be 
 

modified

 igneous 
 rock, 
 which 
 hypothesis 
 is 
 confirmed 
 by 
 the 
 outlines 
 

of

 the 
 outcrops 
 indicated 
 on 
 the 
 map. 
 Some 
 distance 
 from 
 the 
 top 
 of 
 

the

 pass 
 we 
 noticed 
 that, 
 in 
 the 
 crags 
 on 
 the 
 left 
 bank 
 of 
 the 
 upland 
 glen 
 

which

 we 
 were 
 descending, 
 masses 
 of 
 rock, 
 probably 
 from 
 50 
 feet 
 to 
 

about

 300 
 feet 
 thick, 
 exhibited 
 a 
 kind 
 of 
 stratification, 
 indicated 
 by 
 

differences

 of 
 tint, 
 and 
 these 
 dipped 
 clearly 
 northwards, 
 at 
 perhaps 
 an 
 

average

 angle 
 of 
 40°. 
 Beyond 
 this 
 the 
 bed 
 of 
 the 
 glen 
 is 
 interrupted 
 by 
 

a

 range 
 of 
 cliffs. 
 The 
 bottom 
 of 
 the 
 slope 
 is 
 reached 
 by 
 a 
 rapid 
 and 
 

rough

 descent 
 in 
 a 
 north-westerly 
 direction, 
 during 
 which 
 we 
 ob- 
 

served

 that 
 the 
 mica 
 now 
 and 
 then 
 became 
 more 
 silvery, 
 and 
 the 
 

rock,

 as 
 a 
 whole, 
 assumed 
 a 
 less 
 " 
 ancient 
 " 
 aspect. 
 On 
 reaching 
 the 
 

bottom

 the 
 scenery 
 changes, 
 the 
 stream 
 becoming 
 bordered 
 by 
 sloping 
 

pastures

 and 
 copses, 
 and 
 no 
 rock 
 was 
 seen 
 in 
 situ 
 till 
 after 
 passing 
 

the

 Pinzgauer 
 Tauernhaus 
 (3,5-30 
 feet), 
 when 
 a 
 rather 
 fissile 
 chloritic 
 

schist

 crops 
 out. 
 Hence 
 to 
 near 
 Mittersill 
 little 
 rock 
 is 
 seen, 
 what 
 

there

 is 
 being 
 either 
 the 
 normal 
 chloritic 
 schist 
 or 
 green 
 rock 
 of 
 a 
 

not

 very 
 definite 
 character. 
 The 
 lateral 
 torrents, 
 however, 
 bring 
 

down

 blocks 
 of 
 fine-grained 
 rather 
 banded 
 gneisses, 
 darker 
 and 
 

lighter,

 of 
 various 
 gneisses 
 and 
 schists 
 approaching 
 the 
 Lepontine 
 

type,

 with 
 some 
 which 
 appear 
 to 
 belong 
 to 
 the 
 "Thonglimmerschiefer" 
 

series

 ; 
 but 
 shortly 
 before 
 reaching 
 Mittersill 
 we 
 traverse 
 in 
 a 
 shallow 
 

gorge

 a 
 considerable 
 mass 
 of 
 chloritic 
 schist, 
 with 
 a 
 high 
 dip 
 towards 
 

the

 north 
 (Appendix, 
 p. 
 108). 
 It 
 is 
 somewhat 
 calcareous, 
 and 
 corre- 
 

sponds

 with 
 the 
 green 
 schists 
 in 
 the 
 glen 
 north 
 of 
 Windisch-Matrei. 
 

According

 to 
 Yon 
 Hauer's 
 map 
 the 
 associated 
 group 
 of 
 calcareous, 
 

micaceous,

 and 
 chloritic 
 schists 
 extends 
 continuously 
 round 
 the 
 

eastern

 edge 
 of 
 the 
 Central- 
 Gneiss 
 massif, 
 passing 
 from 
 Windisch- 
 

Matrei,

 by 
 the 
 head 
 of 
 the 
 Mollthal, 
 to 
 the 
 valley 
 of 
 the 
 Salza, 
 in 
 

which,

 among 
 level 
 water-meadows, 
 Mittersill 
 is