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AND

 BANDED 
 CRYSTALLINE 
 ROCKS 
 OF 
 THE 
 LIZARD. 
 529 
 

capillary

 attraction 
 into 
 the 
 space 
 (e-f). 
 Similarly 
 the 
 water 
 that 
 

had

 been 
 flowing 
 along 
 (c-d) 
 would 
 find 
 its 
 way 
 into 
 the 
 spaco 
 

below

 it. 
 As 
 a 
 result 
 of 
 this 
 slow 
 percolation 
 chemical 
 action 
 

would

 be 
 set 
 up 
 in 
 the 
 body 
 of 
 the 
 rock 
 between 
 the 
 planes 
 of 
 

lamination.

 Now 
 suppose 
 the 
 flow 
 along 
 the 
 planes 
 (a-b) 
 and 
 (c-d) 
 

Fig.

 5. 
 

/

were

 to 
 be 
 reestablished, 
 the 
 liquid 
 in 
 the 
 rock 
 above 
 (a-b) 
 would 
 

be

 drained 
 off 
 by 
 (a-b) 
 and 
 the 
 water 
 in 
 the 
 space 
 (e-f) 
 would 
 be 
 

drained

 by 
 (c-d) 
 : 
 for 
 the 
 flow 
 along 
 (a-b) 
 and 
 (c-d) 
 being 
 more 
 easy 
 

than

 in 
 a 
 transverse 
 direction, 
 the 
 supply 
 from 
 (a-b) 
 into 
 (e-f), 
 and 
 

from

 (c-d) 
 into 
 the 
 space 
 below, 
 would 
 decline, 
 and 
 the 
 force 
 of 
 

gravity

 would 
 carry 
 the 
 water 
 in 
 (e-f) 
 downwards 
 into 
 (c-d). 
 

That

 such 
 periodical 
 currents 
 would 
 be 
 established 
 in 
 water- 
 

bearing

 strata 
 adjoining 
 the 
 roots 
 of 
 active 
 volcanoes 
 I 
 think 
 highly 
 

probable.

 Considering 
 the 
 amount 
 of 
 water 
 in 
 the 
 form 
 of 
 steam 
 

given

 off 
 by 
 active 
 volcanoes, 
 and 
 considering 
 the 
 tremendously 
 

explosive

 character 
 of 
 the 
 periodic 
 discharges 
 from 
 some 
 craters, 
 

powerful

 suction 
 must, 
 I 
 think, 
 follow 
 each 
 explosive 
 discharge, 
 

which

 must 
 affect 
 the 
 water-bearing 
 strata 
 in 
 which 
 the 
 roots 
 of 
 

volcanoes

 are 
 planted. 
 This 
 powerful 
 suction* 
 and 
 pumping 
 action 
 

is

 sufficient, 
 it 
 seems 
 to 
 me, 
 to 
 account 
 for 
 a 
 periodic 
 capillary 
 flow 
 

of

 water 
 in 
 strata 
 within 
 the 
 range 
 of 
 a 
 volcano's 
 influence 
 com- 
 

parable,

 as 
 regards 
 the 
 character 
 of 
 the 
 flow, 
 with 
 the 
 circulation 
 of 
 

fluids

 in 
 the 
 tissues 
 of 
 animal 
 and 
 vegetable 
 bodies. 
 

That

 our 
 ancient 
 volcanoes 
 did, 
 as 
 a 
 matter 
 of 
 fact, 
 exhibit 
 ex- 
 

plosive

 action 
 of 
 the 
 most 
 powerful 
 kind 
 and 
 on 
 the 
 most 
 extensive 
 

scale,

 no 
 one 
 can 
 doubt 
 who 
 has 
 examined 
 the 
 extensive 
 deposits 
 

of

 the 
 Charnwood 
 Forest, 
 which 
 range 
 from 
 the 
 finest 
 ash 
 to 
 coarse 
 

agglomerates

 in 
 which 
 the 
 blocks 
 are 
 several 
 feet 
 in 
 diameter. 
 Prof. 
 

Bonney

 and 
 others 
 tell 
 us 
 that 
 the 
 Charn 
 wood-Forest 
 deposits 
 be- 
 

long

 to 
 the 
 Archaean 
 series 
 ; 
 and 
 at 
 all 
 events 
 no 
 one 
 will 
 deny 
 that 
 

they

 belong 
 to 
 a 
 pre-Carboniferous 
 age. 
 

In

 these 
 Charnwood-Forest 
 rocks 
 ash 
 predominates 
 and 
 lava-beds 
 

are

 very 
 subordinate. 
 Ash-beds, 
 moreover, 
 according 
 to 
 the 
 Geo- 
 

logical

 Survey 
 Keport 
 already 
 quoted, 
 are 
 to 
 be 
 found 
 in 
 abundance 
 

in

 Cornwall 
 itself, 
 and 
 the 
 beds 
 that 
 contain 
 them 
 are 
 as 
 old, 
 according 
 

to

 present 
 received 
 opinion, 
 as 
 the 
 Ordovician 
 age. 
 

That

 water 
 has 
 flowed, 
 or 
 percolated, 
 through 
 the 
 Lizard 
 born- 
 

blende-schists

 in 
 the 
 direction 
 of 
 the 
 banding 
 is 
 not 
 altogether 
 a 
 

matter

 of 
 inference 
 or 
 theory. 
 In 
 the 
 following 
 illustration 
 (fig. 
 6) 
 

I

 give 
 a 
 sketch 
 taken 
 from 
 one 
 of 
 those 
 banded 
 hornblende-schists. 
 

 The 
 vigour 
 of 
 the 
 response 
 to 
 this 
 suction 
 would, 
 of 
 course, 
 depend 
 on 
 the 
 

porosity

 of 
 the 
 rock 
 and 
 the 
 " 
 head" 
 of 
 the 
 water 
 permeating 
 it. 
 

Q.J.G.

 S. 
 No. 
 179.