o th e r fa c ts (p . 3 8 1 ) , a re q u i te in te llig ib le to m e from th e b rie fn e s s , w ith
w h ic h th e y a r e a llu d e d to . M . Ag a ssiz says ( p . S 7 o ), “ T h e e r r a tic
b lo ck s o f th e J u r a e v e ry w h e r e rep o se o n p o lish e d su rfa c e s, a ll th o s e a t
le a s t w h ic h h a v e n o t b e e n c a rrie d b e y o n d th e c r e s t o f o u r m o u n ta in s , a u d
w h ic h h a v e n o t fa lle n to th e b o ttom o f o u r lo n g itu d in a l va lley s, a s m ay b e
se en th ro u g h o u t th e v a lle y s o f th e C re u x d u V e n t. B u t th e y d o n o t
re p o s e im m e d ia te ly u p o n th e s e p o lish e d su rfa c e s. W h e r e v e r th e ro u n d e d
p e b b le s w h ic h a c com p a n y tile g r e a t b lo ck s h a v e n o t b e e n r em o v e d b y
s u b s e q u e n t in flu e n c e s , i t is r em a rk e d t h a t sm a ll b lo ck s, in o th e r wo rd s
p e b b le s o f d iff e re n t sizes, fo rm a b e d o f som e in ch e s , a n d s om e tim e s ev en
o f m an y fe e t, u p o n w h ic h th e g r e a t a n g u la r b lo ck s re p o s e . T lie s e p e b b le s
a r e a ls o m u c h ro u n d e d , ev en p o lish e d , a n d a r e h e a p e d u p in su c h a way
th a t th e la rg e r a r e a b o v e th e sm a lle r, a n d t h a t th e la s t o fte n pa ss b e low
in to a fin e s a n d , ly in g im m e d ia te ly o v e r th e p o lish e d su rfa c e s. T h is
o r d e r o f s u p e rp o s itio n , w h ic h is c o n s ta n t, is o p p o s e d to a ll id e a o f a
t r a n s p o r t b y c u rr e n ts ; fo r in th is l a t t e r c ase th e o rd e r o f th e su p e rp
o s itio n o f th e p e b b le s w o u ld h a v e b e e n p re c is e ly rev e rs e d .” F u r th e r o n
(p . 3 7 9 ) h e r em a rk s t h a t th e a c tio n o f th e g lac ie rs is im m e n s e ; “ fo r
th e s e m asses, c o n tin u a lly m o v in g u p o n e a ch o th e r , a n d o n th e su rfa c e ,
b ru is e a n d g r in d d ow n e v e ry th in g m o v eab le , a n d p o lish th e s o lid su rfa c e s
oil w h ic h th e y re p o s e ; a t tlie s am e tim e t h a t th e y p u s h b e fo re th em a ll
t h a t th e y e n c o u n te r , w ith a fo rc e w h ic h is irre sis tib le . I t is to th es e
m o v em e n ts ( o f th e g r e a t s tr a tum o f ice ) w e m u s t a tt r ib u t e th e s tr a n g e
s u p e rp o s itio n o f tb e ro lle d p e b b le s , a n d o f th e san d , w h ic h im m e d ia te ly
r e p o s e s u p o n th e p o lish e d su rfa c e s ; a n d i t is u n q u e s tio n a b ly to th e
g r a tin g o f th is s a n d u p o n th e s e su rfa c e s t h a t th e fin e lin e s w h ic h w e fin d
(p re v io u s ly c om p a re d to th e s c ra tch e s m ad e b y a d iam o n d o n glass) a re
ow in g , a n d w h ic h w o u ld n e v e r h a v e e x is te d , i f th e s a n d h a d b e e n a c te d
u p o n b y a c u r r e n t o f w a te r.” N ow i t m ay b e d em a n d e d , b y w h a t p o s s
ib le m ea n s c an su c h v io le n t a c tio n a rr a n g e th e la rg e p e b b le s a b o v e th e
sm a lle r o n e s , a n d th e s e a g a in a b o v e th e s a n d ? T h e fac t a p p e a r s to m e
u t te r ly in e x p lic a b le o n th is view . A g a in i t is sa id , t h a t th e su rfa c e o f
th e ro c k is m a rk e d b y fu rrow s a n d g ib b o sitie s , a s well as b y s c ra tch e s , a n d
t h a t th e s e “ n e v e r fo llow th e d ire c tio n o f th e s lo p e o f th e m o u n ta in , b u t
a r e o b liq u e a n d lo n g itu d in a l ( th a t is, in th e lin e o f th e m o u n ta in , a n d
th e r e fo r e n e a rly h o r iz o n ta l) , a d ire c tio n w h ic h e x c lu d e s e v e ry id e a o f a
s tre am o f w a te r b e in g th e c a u se o f th e s e e ro sio n s.” W h a t e x p la n a tio n
will i t b e b e lie v e d is o ffe re d fo r th is fa c t ?—- I t is, t h a t th e fin e lin e s a n d
fu rrow s “ m u s t h a v e r e s u lte d from th e m u ch g r e a te r f a c ility w h ic h th e ice
h a d in d ila tin g its e lf in th e d ire c tio n o f t h e g r e a t Swiss v a lley , th a n tra n s -
vei'sely, co n fin ed as i t w e re b e tw e e n th e J u r a a n d th e A lp s .” !
I will n ow e n d e a v o u r to sh ow h ow fa r th e s e v e ry c u rio u s fac ts, w h ich
w e ow e to M . A g a s s iz 's o b s e rv a tio n , c an b e e x p la in e d b y th e th e o ry o f
flo a tin g ice : a n d th e th e o ry , I m ay ad d , i f a p p lic a b le to th is c a se , so lv e s
t h a t w h ic h p r e s e n ts f a r g r e a te r d ifficu ltie s , tlia n a n y o th e r o f th e k in d
in E u ro p e . I s h o u ld firs t s ta t e th a t I m ak e tw o assumptions, a n d i f tlie se
b e re je c te d , th e th e o ry is n o t a p p lic a b le to th e case o f th e e rr a tic b lo ck s
o f t h e A lp s :— first, t h a t a n a rm o f th e s e a e x te n d e d b e tw e e n th e .Tura a n d
th e A lp s , d u r in g t h a t p e rio d in w h ic h , as I h a v e b e fo re sh ow n , i t is p ro b a b le ,
th a t th e p ro p o r tio n a l a re a o f w a te r in E u r o p e w a s g r e a te r, a n d c e rta in ,
th a t th e p ro d u c tio n s o f th e la n d a n d w a te r h a d a m o re tro p ic a l c h a ra c te r ,
a t th e sam e tim e t h a t th e sn ow -lin e d e s c e n d e d low e r. T h e a g e o f th e
M o la s se , w h ic h o c c u p ie s th is a re a , b e tw e e n th e J u r a a n d A lp s , h a s n o t
b e e n a c c u r a te ly d e te rm in e d ; b u t i t is s u p p o s e d to b e m io c e n e , a n d is
s a id to c o n ta in le a v e s o f th e C h am æ ro p s , a g e n u s o f p a lm s , a t p r e s e n t
fo u n d f u r th e r from th e e q u a to r th a n a n y o th e r k in d . I t is n o t, h ow e v e r,
e v id e n t t h a t th e M o la s se w a s d e p o s ite d b y th e s e a d u r in g th e la t e s t
p e rio d , w h e n i t o c c u p ie d a c o n fin e d lim it b e tw e e n th e A lp s a n d J u r a ;
b u t e v e n i f th is s h o u ld b e fo u n d to b e th e c a se , i t w o u ld b e r a sh in a n y
o n e p o s itiv e ly to c o n c lu d e t h a t g la c ie rs c o u ld n o t h a v e d e sc e n d e d to th o
s h o re s o f a se a, o n w h ic h th e C h am æ ro p s flo u rish e d , a f te r t h a t w e k n ow
th e y d e s c e n d in th e s o u th e r n h em is p h e re so n e a r th e lim its o f se v era l
tro p ic a l fo rms.
M y s e c o n d assumption is, t h a t th e e le v a tio n o f th is m u c h o f S w itz e r la
n d , w h e n e v e r i t to o k p lac e , was s low a n d g r a d u a l : th is is s u p p o r t e d b y
th e s tro n g e s t a n a lo g ie s o f S o u th A m e ric a , S c a n d in a v ia , a n d o th e r p a r ts o f
t h e w o rld ; w h ils t o n th e o th e r h a n d , t h e assumption t h a t i t h a d b e e n s u d d e n ,
w o u ld b e u n s u p p o r te d b y a s in g le a s c e r ta in e d fa c t in n a tu r e . N ow , as
th e n um e ro u s masses o f ic e , w h ic h fall from th e g lac ie rs a t th e h e a d o f th e
so u n d s o n th e S o u th A m e ric a n c o a s t, ave slow ly d r if te d o u tw a rd s (ow in g
to th e fre sh w a t e r flow in g in from th e fo o t o f th e g lacière), a n d in th e m o re
o p e n c h a n n e ls a r e le f t to b e a c te d o n b y th e w in d s a n d c u r r e n ts ; so m u s t
i t h a v e b e e n w ith th e iceb e rg s from th e g la c ie rs o f th e A lp s , s itu a te d in
th e s am e la titu d e , a n d u n d e r s im ila r c o n d itio n s . T h e s e ice b e rg s w o u ld in
m o s t cases b e d r iv e n o n som e p a r t o f th e s u rro u n d in g s h o re ; b u t from
flo a tin g d e e p th e y w o u ld g ro u n d a l it tl e way from th e b e a c h , a n d th e n
b e in g p a c k e d to g e th e r, a n d d r iv e n to a n d fro , as th e w in d s c h a n g ed , a n d as
th e tid e s ro se a n d fell, w o u ld th e y n o t, lik e a g la c ie r o n th e la n d , th o u g h
in a le s s e r d eg re e , “ b ru is e a n d g r in d d ow n e v e ry th in g a n d p o lish th e s o lid
su rfa c e , o n w h ic h th e y r e p o s e d ? ” I n th e ra p id s o f th e N o r th A m e ric a n
riv e rs, o v e r w h ic h la rg e b o d ie s o f ice a r e d riv e n , c a rry in g w ith th em p e b b
le s a n d fra gm en ts o f ro ck s, I am in fo rm e d b y D r . R ic h a rd s o n , t h a t th e
p r im itiv e ro ck s a re s c o o p ed a n d lio llow ed , a n d h a v e t h e i r su rfa c e s p o lish e d
a u d glossy. D r . R ic h a rd so n , h ow e v e r, is n o t p r e p a r e d to say, w h e th e r th is