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84

 PEOF. 
 T. 
 G. 
 BONNET 
 ON 
 TWO 
 TEAVEBSES 
 OF 
 THE 
 

over

 the 
 crystalline 
 rocks 
 of 
 the 
 central 
 range, 
 from 
 which, 
 however, 
 

they

 have 
 been 
 almost 
 entirely 
 removed 
 by 
 denudation. 
 Of 
 the 
 

igneous

 rocks 
 of 
 the 
 region, 
 especially 
 those 
 of 
 the 
 Southern 
 Tyrol, 
 

it

 is 
 needless 
 to 
 speak. 
 The 
 above-named 
 " 
 Thonschiefer" 
 with 
 the 
 

lower

 part 
 of 
 which 
 some 
 chloritic 
 schists 
 and 
 crystalline 
 limestones 
 

are

 associated, 
 is 
 extensively 
 developed 
 in 
 the 
 Eastern 
 Alps. 
 The 
 name 
 

"

 Thonschiefer 
 " 
 is 
 vague 
 ; 
 for, 
 if 
 I 
 mistake 
 not, 
 it 
 might 
 be 
 applied 
 

to

 either 
 a 
 claj^-slate 
 or 
 an 
 aluminous 
 schist. 
 Certainly 
 the 
 rock 
 is 
 

not

 the 
 former, 
 though 
 sometimes 
 locally, 
 when 
 greatly 
 crushed, 
 it 
 

presents

 a 
 stroug 
 resemblance 
 to 
 it. 
 In 
 the 
 extensive 
 rock-collec- 
 

tion

 of 
 the 
 Innsbruck 
 Museum 
 the 
 series 
 is 
 called 
 " 
 Thon-glimmer- 
 

Schiefer"

 which 
 is 
 made 
 less 
 ambiguous 
 by 
 the 
 inserted 
 word. 
 I 
 

have

 a 
 difficulty 
 in 
 finding 
 an 
 English 
 equivalent. 
 Clay 
 -mica- 
 

schist

 is 
 misleading, 
 aluminous 
 mica-schist 
 awkward 
 ; 
 upper 
 mica- 
 

schist

 is 
 open 
 to 
 objection 
 as 
 involving 
 an 
 assumption 
 as 
 to 
 strati- 
 

graphy

 ; 
 phyllite 
 suggests 
 too 
 fine-grained 
 a 
 rock 
 ; 
 so 
 I 
 propose, 
 at 
 

present,

 in 
 the 
 poverty 
 of 
 English 
 nomenclature, 
 to 
 retain 
 the 
 

German

 term 
 " 
 Thonglimmerschiefer." 
 

(/3)

 The 
 Pusterthal 
 and 
 Neighbourhood. 
 

"We

 travelled 
 by 
 railway 
 up 
 the 
 valley 
 of 
 the 
 Adige, 
 traversed 
 

the

 igneous 
 rocks 
 in 
 the 
 neighbourhood 
 of 
 Bozen, 
 and 
 in 
 due 
 course 
 

reached

 the 
 " 
 Thonglimmerschiefer 
 " 
 south 
 of 
 Klausen 
 *. 
 With 
 the 
 

members

 of 
 this 
 group 
 previous 
 visits 
 to 
 the 
 Tyrol 
 had 
 already 
 

made

 me 
 fairly 
 familiar, 
 and 
 I 
 could 
 see, 
 even 
 as 
 I 
 passed 
 by, 
 that 
 

though

 they 
 varied 
 somewhat 
 in 
 texture 
 and 
 hardness, 
 the 
 dominant 
 

rock

 is 
 a 
 moderately 
 soft, 
 dull 
 lead-coloured 
 mica-schist, 
 in 
 which 
 the 
 

individual

 films 
 are 
 not 
 coDspicuous 
 to 
 the 
 eye, 
 at 
 any 
 rate 
 at 
 the 
 

first

 glance. 
 This 
 obscuration 
 of 
 the 
 true 
 structure 
 is 
 very 
 probably 
 

the

 result 
 of 
 crushing. 
 The 
 apparent 
 foliation 
 is 
 a 
 cleavage-foliation 
 

the

 conspicuous 
 surfaces 
 are 
 " 
 sheen 
 surfaces," 
 which 
 exhibit 
 a 
 

peculiar

 gloss, 
 looking 
 sometimes 
 like 
 the 
 polished 
 black-lead 
 of 
 a 
 

fire-grate.

These

 macroscopic 
 characteristics 
 are 
 very 
 commonly 
 so 
 general 
 

and

 so 
 uniform, 
 that 
 one 
 can 
 recognize 
 the 
 rock 
 with 
 certainty 
 even 
 

from

 a 
 railway-train 
 f. 
 Our 
 first 
 halt 
 was 
 made 
 at 
 Brunecken, 
 

where.

 the 
 " 
 Thonglimmerschiefer" 
 series 
 is 
 well 
 exposed 
 close 
 to 
 the 
 

town,

 and 
 presents 
 some 
 interesting 
 variations. 
 The 
 picturesque 
 

old

 castle 
 stands 
 on 
 a 
 craggy 
 mound 
 of 
 white 
 crystalline 
 limestone 
 

(Appendix,

 p. 
 107) 
 ; 
 this, 
 on 
 the 
 southern 
 side, 
 is 
 distinctly 
 " 
 bedded 
 " 
 

like

 an 
 ordinary 
 limestone, 
 and 
 dark 
 streaks 
 occur 
 in 
 the 
 rock 
 

parallel

 with 
 this 
 structure. 
 The 
 beds 
 are 
 much 
 twisted 
 about, 
 but 
 

they

 appear 
 to 
 have 
 a 
 general 
 strike 
 about 
 S.S.E., 
 with 
 a 
 high 
 dip. 
 

On

 the 
 northern 
 side 
 a 
 little 
 mica-schist 
 crops 
 out, 
 apparently 
 in 
 

situ

 ; 
 but 
 its 
 strike 
 is 
 nearer 
 E.S.E. 
 Then 
 comes 
 (after 
 a 
 short 
 

 In 
 several 
 places, 
 as 
 I 
 have 
 myself 
 seen 
 and 
 have 
 learnt 
 from 
 the 
 Innsbruck 
 

Museum,

 the 
 dolomites 
 of 
 the 
 Italian 
 Tyrol 
 rest 
 on 
 either 
 " 
 Thonglimmer- 
 

schiefer^

 or 
 mica- 
 schist. 
 

t

 I 
 have 
 verified 
 this 
 assertion 
 many