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290 T I E R R A l i E I . I - 'UEGO. June, 1834.
very great weight in support of the mass of positive evidence
whioh Mr. Lyell* has brought to bear upon the question.
a n d th e g r e a te r n um b e r o f e v e n th e s am e c o lo u re d v a rie ty , as th e g r a n itic
ro ck , o n wh ic li th e y re s t, th e case n e e d n o t b e c o n s id e re d . S e co n d ly , in a
l a t e n um b e r o f tile M a d ra s J o u rn a l, D r . B e iiz a h a s d e s c rib ed som e e rr a tic
b lo ck s ly in g o n a p la in b e tw e e n th e N e ilg h c r rie s ( la t. 1-2° N .) a n d M ad ra s .
H o s ta te s th a t th e fo u n d a tio n -ro c k o f th e c o u n try is gneiss, “ wliilc th e
g r a n ite c lu s te rs a re m o re e le v a ted , a n d a ffe c t c itlie r a p r ism a tic fo rm , o r
a r e p ile d u p one on the other, lik e logging stones.” D r . B e iiz a h a d th e
k in d n e s s to in fo rm m e t lia t th e s e masses a r e v e ry la rg e , a n d t h a t se v era l
a r e p ile d o n e u p o n th e o th e r . A g a in , B ro n g n iav t says ( l a b l e a i i d e
T e r ra in s , p . 8 3 ) , “ O n c ite au ssi d a n s IT n d e , a n p ay s d ’H y d e r a b a d
( la t. 17 ° N .) , des b lo cs hiormes d e g ra n ite , amoneclcs les iins s n r les
a u t r e s ” (D e lu c n e v e u ). E v e ry o n e m u s t d raw h is own co n c lu s io n s from
th e s e a c c o u n ts , re g a rd in g th e p ro b a b ility o f e r r a tic b lo ck s b e in g lie a p e d
u p , o n e u p o n th e o th e r , like logging stones. T h e s am e d o u b t lik ew ise
p a r tly a p p lie s to th e M a c a o case. W ith re s p e c t to th e b o u ld e r s o f E ly d e ra-
b a d , D r .T . C h r is tie h a s d is tin c tly s ta te d (E d in . N ew P h i l . J o u r ., O c t. 1828,
p . 10-2), t h a t th e y a r e in situ, a n d h a s e x p la in e d th e i r o rig in . F o r my
ow n p a r t , I c a n n o t fo rg e t t h a t wlio le g r a n itic h ills a t th e C a p e o f
G o o d H o p e , w h ic h , from w e a th e r in g , h a v e a s sum e d a h o iild e r- lik e fo rm,
w e re o n c e d e s c rib ed as t r a n s p o r te d m asses. T lie tw o n e x t cases d o n o t
p ro p e r ly com e u n d e r c o n s id e ra tio n , fo r th e y re f e r to m asses ly in g in th e
valleys o f lo fty m o u n ta in s . W e m u s t n o t o v e rlo o k su c h a c c id e n ts as
b u r s tin g o f lak e s , e a rth q u a k e s , a n d th e a c tio n o f fo rm e r c o a st-lin e s. H e lm s ,
in h.is T ra v e ls (E n g lish tra n s la tio n , p . 4 5 ) , s ta te s h e was a s to n ish e d to
fin d th e h ig h e s t sn ow -c a p p ed m o u n ta in s n e a r P o to s i ("20° N .) co v e red
w itli a s tr a tum o f ro u n d e d g r a n itic s to n e s . H e su p p o s e s th e y m u s t h a v e
c om e from T u c nm a n , w h ic h is se v era l h u n d r e d m ile s d i s t a n t . y e t a t p . 55
h e says, a t lo c a lla ( a few le a g u e s o n ly from P o to s i) , “ a mass o f g r a n ite
m a n y m iles in len g tli, rise s in h u g e w e a th e rb e a te n ro ck s th e w h o le
a c c o u n t is to m e q u i te u n in te llig ib le . L a s tly , M . G a y (A n n a le s des
S c ien c e s , 1 8 3 8 ) d e scrib es g r a n itic b o u ld e r s w ith in th e v a lle y o f C a u q u e n e s
( la t . 8 3 ° -3 4 ° S .), in th e C o rd ille ra . I v is ite d th is p lac e ; th e b o u ld e r s a n d
p e b b le s a re n o t la rg e , a n d th o s e b e y o n d th e m o u th o f th e v a lle y a r e sma ll.
T h e case d id n o t a p p e a r to m e n e a rly so e x tr a o rd in a ry as i t seem s to h av e
s tru c k .M. Gay . I c a n n o t a g re e w ith h is a s s e rtio n t lia t th is ro c k is n o t
fo u n d in t h a t p a r t o f th e C o rd ille ra ; b u t th is is a s u b je c t w h ic h I slia ll
discu ss in a f u tu r e w o rk .
! T lie a b s en c e o f g r e a t em b e d d e d fra gm e n ts in th e fo rm a tio n s o f th e
s e c o n d a ry ep o c h , w h e n w e k n ow t h a t th e c lim a te w a s o f a m o re tro p ic a l
c h a ra c te r , is a fa c t o f th e s am e k in d .
f
June, 1834. R E CAP I TU LAT IO N. 391
The circumstance of a luxuriant vegetation witli a tropical
character so largely encroaching on the temperate zones,
under the same kind of climate that allows of a limit of
perpetual snow of little altitude, and consequent descent of
the glaciers into the sea, is very important ; because it has
been argued, with great apparent truth, that as there is the
strongest presumptive evidence of a gradual cooling down of
the climate (or rather of a less favourable state for trojiical
productions) in Europe, it is most unphilosophical to imagine
that formerly glaciers could have acted where they do not now
occur. It may be asked ; what are the circumstances in the
southern hemisphere that produce such results ? Must we
not attribute them to the large proportional area of water ; and
do not plain geological inferences compel us to allow, that
during the epoch anterior to the present, the northern hemisphere
more closely approached to that condition, than it
now does ?
We are all so much better acquainted with the position of
places in our own, than in any other quarter of the globe,
that I will recapitulate what is actually taking place in the
southern hemisphere,! only transporting in imagination each
part to a corresponding latitude in the north. On this supposition,
in the southern provinces of France, magnificent
forests, intwined by arborescent grasses, and the trees loaded
with parasitical plants, would cover the face of the country. In
the latitude of Mont Blanc, but on an island as far eastward
as central Siberia, tree-ferns and parasitical orcliideæ would
tlirive amidst the thick woods. Even as far north as central
Denmark, Immming-birds might be seen fluttering about
delicate flowers, and parrots feeding amidst tlie evergreen
woods, with which the mountains would be clothed down to
the water’s edge. Nevertheless, tlie southern part of Scot-
* A n n iv e rs a ry A d d re s s to th e G eo lo g ic a l S o c iety , F e b . 19, 1836, p. 3 0 ;
a n d P r in c ip le s o f Geo lo g y , vol. i., p . 2 69, a n d vo l. iv., p . 4 7 , fifth e d itio n .
t I t is in th e s o u th e rn h em isp h e re t h a t w e fin d e le p h a n ts , rh in o c e ro se s ,
liip p o p o tom u s e s , a n d lio n s, as fa r s o u th as la t. 3 4 ° 3 5 '. In S o u th A m e ric
a th e j a g u a r o ccu rs in 42°, a n d th e p um a lu 5 3 °.
u 2