is c a u se d b y th e p a s sa g e o f th e ice o r o f th e p e b b le s .* A lth o u g h th e iceb
e rg s m ig lit b e d r if te d from s id e to s id e o f th e so u n d , i f th e y w e re m o v ed
a f te r h a v in g g ro u n d e d , i t w o u ld b e a lo n g th e s h o re b y th e s e t o f th e c u r r
e n ts o r w in d , a n d p e rh a p s s lig h tly u p a n d d ow n b y th e tid a l c h a n g es .
W o u ld n o t th e n e c e s s a ry e ffe c t o f th is be, th a t th e s c ra tch e s fo rm e d b y
th e s a n d g r a tin g b e tw e e n th e ro ck s a n d th e b o ttom o f th e ic eb e rg s s h o u ld
b e , w ith som e ir r e g u la r itie s , lo n g itu d in a l, o r (from th e e ffe c t o f th e tid a l
m o v em e n t) o b liq u e ? A n d a s th e m o u n ta in s s low ly em e rg e d d u r in g ag es,
e v e ry p a r t w’o u ld b e th u s a c te d o n ; a n d c o n s e q u e n tly th e wh o le su rfa c e
w o u ld b e m a rk e d b y lo n g itu d in a l s c ra tch e s .
T h e iceb e rg s o n th e S o u th A m e ric a n c o a st som e tim e s tr a n s p o r t a n g u la r
f ra gm e n ts o f ro ck , to th e d is ta n c e o f m an y m ile s from th e g lac ie r wh en c e
th e y w e re d e ta c h e d ; a n d as th e w in d s a n d curj-ents g e n e ra lly h a v e suffic
ie n t s te a d in e s s to d riv e a n y flo a tin g o b je c t soon o n sh o re , ( a s is k n ow n
to b e th e case w ith a c ap siz e d b o a t, a b a rr e l, o r flo a tin g c a rc a ss, & c .), so
th e b lo ck s o f ro c k w o u ld b e g en e ra lly \ la n d e d o n th e sh o re s o f th e c h a n -
* I t m u s t b e rem em b e re d , t h a t I am h e r e c o n s id e rin g th e e ffe c t o f iceb
e rg s, in in la n d a n d p ro te c te d so u n d s . D r . R ic h a rd so n te lls m e, t h a t th e
g r e a t ic eb e rg s in th e A r c tic s e a a r e p a c k e d to g e th e r, a n d a r e d r iv e n w ith
su c h fo rc e a g a in s t th e sh o re , th a t th e y p u s h u p b e fo re th em , to th e h e ig h t
o f s e v e ra l f e e t, e v e ry p e b b le a n d b o u ld e r w h ic h lie s o n th e b o ttom ; a n d
c o n s e q u e n tly th e su bm a r in e led g e s o f ro c k a re k e p t a b s o lu te ly b a re . I f a
f ra gm e n t w^ere to b e w^edged b e n e a th o n e o f th e s e m o u n ta in -m a ss e s o f ice,
w h e n fo rc e d u pw a rd w ith su ch o v e rw h e lm in g p ow e r, i t is im p o s s ib le to
d o u b t t h a t th e u n d e rly in g su rfa c e o f s o lid ro c k w o u ld b e d e e p ly sco red .
A s i t is k n ow n t h a t th e s h in g le o n m o s t b e a ch e s h a s a ten d e n c y to tra v e l
in o n e d ire c tio n , so m u s t th e ic e b e rg s ; a n d h e n c e we m ay c o n je c tu re ,
t h a t th e gro o v es, w o u ld g e n e ra lly b e s lig h tly o b liq u e to th e lin e o f c o a st,
a n d p a ra lle l to e a ch o th e r .
j- W e m ig h t e x p e c t t h a t th e y w o u ld sometimes b e la u n c h e d in to th e
d e e p , w h ils t o n th e i r pa ssag e . M . C h a r p e n tie r (Edinburgh N ew Phil,
Journal, vol. x x i., p . 2 1 7 ) o b se rv e s , s p e a k in g o f a n o th e r th e o ry , “ T h is
v iew is e q u a lly in su ffic ien t to a c c o u n t fo r th e e x tr a o rd in a ry p o s itio n o f
im m e n se s in g le b lo ck s, w h ic h we s om e tim e s fin d p l a n t e d v e rtic a lly in th e
so il, in th e valleys, as o n th e sid e s o f a m o u n ta in , a n d s p lit u p th ro u g h o u t
th e i r w h o le e x te n t from to p to b o ttom ,—a p h e n om e n o n w h ic h w o u ld
fo rc e u s to b e lie v e t h a t th e s e b lo ck s , h a d fa llen p e rp e n d ic u la r ly from a
c e r ta in h e ig h t o n th e v e iy sp o ts w h e re w e n ow se e th em , a n d h a d b e e n
r e n t a s u n d e r b y th e fall, in to th e s e v e ra l fra gm en ts ly in g n e a r o n e a n o th
e r .” INI. C h a rp e n tie r c o n s id e rs th is ow in g to th e fra gm en ts h a v in g fallen
th ro u g h fissures in th e e n o rm o u s g lac ie rs, w h ic h , as h e b e liev e s, e x te n d e d
from th e A lp s , acro.ss th e la k e o f G e n e v a , a n d u p th e J u r a . T h e e x p la n a t
io n a b o v e su g g e sted is, t it le a s t, a s s im p le a s th is .
n e ls b e tw e e n th e A lp in e r an g e s , a n d n o t d ro p p e d in th e in te rv e n in g
sp a ce s. I f a n y p o in te d ro c k c am e so n e a r th e su rfa c e t h a t a flo a tin
g mass o f ice, th u s c h a rg e d , g ro u n d e d o n it, th e b lo c k w o u ld , w h e n th e
ice m e lte d , b e th e r e le ft. B u t i t m ay b e a sk ed , w o u ld th e b lo c k s u su a lly
b e d e p o s ite d o n th e b a r e su rfa c e o f th e ro c k y b o ttom o i f th e sh o re , o r on
a n in te rv e n in g la y e r o f g rav e l o r s e d im e n t ? F rom w h a t I h a v e ob.served
w h e n p a s sin g in b o a ts th ro u g h th e c h a n n e ls o f T i e r r a del F u e g o , a n d from
f r e q u e n t e x am in a tio n s o f th e a rm in g s o f th e le a d u s e d in s o u n d in g , I feel
n e a rly s u re t h a t absolutely hare s u bm a r in e ro c k is n o t v e ry c om m o n .
M o re o v e r, w h e r e m a tte r is d e p o s itin g n e a r a sh o re , th e fin e r th e p a rtic le s
a r e , th e fu r th e r th e y a re d r if te d : in a p p ro a c h in g a c o a s t I h a v e a c tu a lly
tra c e d every step in the series, from th e fin e s t s a n d to la rg e p e b b le s . B u t
as th e la n d in a n y c a se is slow ly e le v a te d , th e s am e fo rc e s w h ich c a rr ie d
th e la rg e p e b b le s to a c e rta in d is ta n c e from tb e b e a c h , a n d th e sm a lle r
o n e s to a s till fu r th e r d is ta n c e , will, a f t e r e a ch l it tl e e le v a tio n , c a rry th em
s om ew h a t fu r th e r :— a la y e r o f l it tl e p e b b le s th u s c o v e rin g th e s a n d , a n d
a la y e r o f la rg e p e b b le s th e sm a lle r o n e s . H e n c e , w h e n th e p a r t n e a r th e
s h o re is c o n v e rte d in to d ry la n d , a se c tio n o f th e b e d w h ic h w a s o rig in
a lly th e b o ttom o f th e s e a will n e c e s sa rily sh ow s o lid ro c k c o v e re d b y
s a n d , th is by fin e p e b b le s , a n d th e s e a g a in b y o th e rs , g r a d u a lly in c re a s in g
in size. S u c h th e n , I c o n c lu d e , m u s t h a v e b e e n th e n a tu r e o f th e s u b lit
to r a l d e p o s its o f th e A lp s , d u r in g th e i r a s sum e d s low e le v a tio n . F in a lly ,
as ic eb e rg s o f la rg e siz e w o u ld se ld om b e d riv e n u p o n th e b e a ch o f a s h e e t
o f w a te r, if, lik e th e c h a n n e l b e tw e e n th e J u r a a n d th e A lp s , i t w e re p r o t
e c te d from th e o p e n se a, a n y fra gm en ts o f ro c k tr a n s p o r t e d b y th em w o u ld
h a v e b e e n d ro p p e d som e w a y o u ts id e , a n d th e r e fo r e w h e n u p r a is e d w ith
th e w h o le c o u n try , th e y w o u ld b e fo u n d in m o s t cases r e p o s in g o n b e d s
(w h e r e th e loose m a t t e r h a d n o t b e e n s u b s e q u e n tly rem o v e d ), c h a ra c te
r iz e d b y th e o rd e r o f s u p e rp o s itio n j u s t d e sc rib ed .
S u c h is th e e x p la n a tio n I w o u ld su g g e s t o f th e v e ry c u rio u s facts
o b se rv e d b y M. A g a ssiz . I m a k e n o a s sum p tio n s w h ic h a r e n o t s u p p
o r te d b y s tro n g an a lo g ie s a n d th e fo u n d a tio n o f th e th e o ry— n am e ly , a
c h a n g e o f c lim a te o f a p e c u lia r k in d— c an b e sh ow n b y r e a so n in g , in d e p
e n d e n t o f th e e x is te n c e o f e rr a tic b lo ck s , to b e p ro b a b le in a hig h
d e g re e : w h e th e r th is is th e case w ith th e th e o ry o f M. A g a ssiz , I le a v e
th e r e a d e r to d e c id e .
H a v in g sa id th u s m u c h o n th e s c ra tc h e d ro ck s o f th e A lp s , I am
tem p te d to m a k e a few r em a rk s o n th o s e o f S c o tla n d , d e sc rib ed b y S ir
J am e s H a ll* in h is c e le b r a te d p a p e r (Edinbtirgh Phil. TrnnsacL, vo l. v ii.)
* S ir Jam e s H a ll b e liev e s t h a t e r r a tic b o u ld e r s w'ere t r a n s p o r te d by
d eb acles, w h e n em b e d d e d in ice . H e seem s to h a v e b e e n le d to th is
o p in io n , b y a c le a r p e rc e p tio n o f th e d iffic u lty o f su p p o s in g th e e x is te n c e