Riss or Würm?

98

Riss or Würm?

B y F. E . Z e u n e r ,

London

Z u s a m m e n f a s s u n g . Die Klimaschwankungen des jüngeren Pleistozäns w e r ­ den anhand von drei unabhängigen Gruppen von Beobachtungsmaterial besprochen, nämlich von Schwankungen des Meeresspiegels, den Terrassenunterkanten der Themse und den fossilen Böden der Lößzone von Nordfrankreich bis Niederösterreich. Die gleiche Abfolge von Klimaphasen ergibt sich in jedem Falle. Das Letzte Interglazial weist in der Mitte eine leichte Schwankung auf und war zeitweilig sommer-wärmer als heute. Die folgende Kaltphase war kurz, aber intensiv (Meeresspiegel ca. —100 m), und auf sie folgte eine Warmphase mit durchaus gemäßigtem Klima (Halling-Stage der Themse), welche oft mit dem Letzten Interglazial verwechselt wird. Auf diese Phase folgt die Vereisungsgruppe Weichsel-Würm. Die vorausgehende Kaltphase wird oft als Jungriß bezeichnet, doch ist W ü r m I vorzuziehen, da das vorausgehende Inter­ glazial länger war als das Interstadial zwischen der fraglichen Phase und dem jüngeren Würmkomplex.

S o m m a i r e . La succession des phases climatologiques du Pleistocene superieur est discute aux points-de-vue des occillations du niveau de la mer, des niveaux d'abrasion fluviatiles de la Tamise, et des sols fossiles qui se trouvent dans des coupes de loess du nord de la France, du bassin de Mayence, la Boheme et l'Autriche. Ces temoignages etant d'accord, on obtient une succession generale comme suit: A p r e s l'avant -derniere glaciation, le dernier interglaciare avec une oscillation legerement froide au milieu, mais autrement tempere et m e m e plus chaud que le climat recent pendant l'ete. II suit une glaciation, la phase qu'on a appelee aux Alpes ou Würm I ou Jeune-Riss. Apres cette periode froide, une interstadiaire parfaitement tempere qui la separe du complexe würmien proprement dit. On a souvent pris cette phase interstadiaire (Hailing stage de la Tamise) pour le propre dernier interglaciaire. C'est comme ca qu'on est errive ä l'appellation Jeune-Riss au lieu de W ü r m I qui est preferable, l'interglaciaire entre Riss et la phase froide en question ayant ete plus long que l'interstadiaire qui le separe du Würmien plus recent.

In all areas w h e r e conditions of o b s e r v a t i o n are f a v o u r a b l e , geologists a g r e e that the four m a j o r glaciations r e c o g n i z e d b y P E N C K can b e s u b d i v i d e d into phases.

T h i s applies in p a r t i c u l a r to the A l p s . C o r r e s p o n d i n g evidence has c o m e forth in the periglacial z o n e w h e r e b o t h r i v e r terraces a n d w e a t h e r i n g horizons h a v e revealed s e q u e n c e s of climatic

fluctuations

more complicated

t h a n the original

scheme of P E N C K . T h i s m u l t i p l i c i t y o f c o l d phases has i n e v i t a b l y raised the p r o b l e m of their correct assignment to m a j o r glaciations, a n d the c o n t r o v e r s y which h a s in the last f e w y e a r s d e v e l o p e d o v e r the assignment of a certain g l a c i a l phase t o the Riss G l a c i a t i o n o r the W ü r m Glaciation is m e r e l y an illustration of the dif­ ficulties

w h i c h are b o u n d to arise. Since the forelands of the n o r t h e r n A l p s a r e

the t y p i c a l area f o r t h e s u b d i v i s i o n of the P l e i s t o c e n e glaciations, f o r it w a s h e r e that P E N C K defined the t e r m s G ü n z , M i n d e l , Riss a n d W ü r m , the u n c e r t a i n t y as t o w h a t should b e c a l l e d Riss and w h a t W ü r m is a serious matter.

T h a t this p r o b l e m is not confined to the A l p i n e s e q u e n c e is i n d i c a t e d b y s i m i l a r c o m p l i c a t i o n s that h a v e arisen in o t h e r areas. O n t h e m a r g i n of the S c a n d i n a v i a n ice-sheet, the c h r o n o l o g i c a l p o s i t i o n of the W a r t h e phase has caused c o n s i d e r a b l e difficulty.

In D e n m a r k the c o n n e c t i o n

of the S k ä r u m h e d e series w i t h b o u l d e r

clays is o p e n to discussion. In t h e loess zone of w e s t e r n Europe, a loess

occurs

which has o c c a s i o n a l l y been assigned to the Y o u n g e r Loesses b y o n e g r o u p of i n ­ vestigators a n d to the O l d e r L o e s s e s b y another, for instance at A c h e n h e i m

in

A l s a c e (ZEUNER 1 9 5 2 , p. 1 5 7 , p. 4 0 7 ; 1 9 5 4 ) , In eastern E n g l a n d there is u n v e r t a i n t y about the L i t t l e Eastern G l a c i a t i o n of S O L O M O N , a n d in the M e d i t e r r a n e a n basin the relation of certain eustatic terraces w i t h interstadials of Last Glaciation a g e or w i t h the L a s t Interglacial has b e e n w o r r y i n g s o m e investigators, as illustrated

Riss or W ü r m ?

99

by Caton THOMPSON'S treatise on the Levalloisian culture in N o r t h Africa. It will take s o m e time before a c o m m o n d e n o m i n a t o r can be applied to these local or regional chronologies, and before an agreement is reached about the nomenclature to b e used which is satisfactory to all. Nevertheless the A l p i n e p r o b l e m of „Riss o r W ü r m " being paralleled b y c o r r e s p o n d i n g p r o b l e m s elsewhere, other areas are likely to contribute information which m a y b e helpful in the solution of A l p i n e problems. B r o a d l y speaking the question is one of the length and the duration of the successive temperate phases separating the glacial phases. M o r e information about this is available in the periglacial and pluvial zones than in the immediate vicinity o f the A l p i n e moraines, and the present p a p e r is intended to v i e w the p r o b l e m in the light of such n o n A l p i n e evidence.

A t the outset it is essential to adopt a n o m e n c l a t u r e for the climatic phases of the Pleistocene which is not local. In other w o r d s , in this article (as in other w o r k s of the writer) the terms Riss and W ü r m are restricted to the A l p i n e area, Saale and Weichsel b e i n g those applicable to the Scandinavian ice-sheet, and so forth, and in the general terminology, the t w o c o m p l e x e s of cold phases, with the separation of which w e are concerned, are called Penultimate Glaciation and Last Glaciation. The equation W ü r m = Weichsel = Last Glaciation is k n o w n to b e c o r r e c t in a broad sense, though in detail m a n y controversial points remain.

Fig. 1. Section from the Ebbsfleet Valley to Swanscombe, Lower Thames, illustrating the sequence of climatic phases from the Great Interglacial onwards.

After the cutting of the bench (G-bench) at Swanscombe, aggradition (in two stages) to Tyrrhenian sea-level of the Penultimate Interglacial (33 m above sea-level) with Clactonian II and early Middle Acheulian.

Then occurred erosion to low sea-level, and formation of Main Coombe Rock (soli­ fluction) and of some stream-deposited gravel (Baker's Hoe) in the cold climate of the first phase of the Penultimate Glaciation, with early Levalloisian at Baker's Hole.

Partial removal of the Coombe Rock suggests a slight break in the sequence (? inter­ stadial PG1 A ?), which was followed by deposition of cold gravels (Middle Levalloisian) and loess (second phase of the Penultimate Glaciation).

Aggradation of river gravels to the Main Monastirian sea-level followed in the first part of the Last Interglacial (Upper Gravels at Baker's Hole).

Thereafter the sea-level dropped again, erosion cutting through the Main Monastirian gravels and partly through the loess series. A new rise of the sea-level (Late Monasti­ rian) brought the aggradation of the 'temperate loam' of Burchell, in the second part of the Last Interglacial. This was followed by further phases of down-cutting and solifluction during the Last Glaciation, not illustrated here, but evidenced by the three buried channel benches (see Fig. 2). l

7 «

F.

100

The

E. Zeuner

sequence of e v e n t s is p e r h a p s m o s t conclusively r e p r o d u c e d b y t h e t h a l a s -

sostatic portion of t h e R i v e r T h a m e s , w h e r e the sections of S w a n s c o m b e a n d Ebbsfleet h a v e p r o v i d e d a n u n a m b i g u o u s starting point, whilst an i n v e s t i g a t i o n of the l o n g i t u d i n a l profile of the terraces carried out b y t h e w r i t e r in c o n j u n c t i o n w i t h M r . D a y KIMBALL h a s r e v e a l e d a n u m b e r of r h y t h m s of bench cutting a n d e s t u a r i n e aggradation w h i c h can o n l y correspond to fluctuations of t h e s e a - l e v e l .

Briefly, these sections (fig. 1; discussed in ZEUNER 1 9 5 2 , p. 1 9 3 , and 1 9 4 5 , p. 1 2 7 ) s h o w that f o l l o w i n g t h e G r e a t I n t e r g l a c i a l t w o cold p h a s e s occurred, t h e second of which witnessed the deposition of the m a j o r part of the loess in K e n t . F o l l o w i n g these cold phases c o u p l e d w i t h a l o w s e a - l e v e l , the s e a - l e v e l rose to a b o u t 1 8 m., t h e T h a m e s adjusting itself to it b y the f o r m a t i o n of the T a p l o w T e r r a c e . A second h i g h s e a - l e v e l is indicated b y the U p p e r F l o o d Plain T e r r a c e at a b o u t 7 . 5 m. T h a t these t w o correspond to t h e M a i n a n d L a t e M o n a s t i r i a n shore-lines r e c o g n i z e d o n the coasts of the A t l a n t i c and M e d i t e r r a n e a n w i l l b e difficult to refute.

HENLEY

WINDSOR

KINGSTON

CITY

DARTFORD

OF

160

LONDON

140 120 100

80 60 40 20

—

—.,

vooe/o/o/n"

-—

0 -20 -40

London Cloy

-60

/Chalk

MILES 1

0

10

1

20

I

1

30

40

50

60

70

80

Fig. 2. The erosional benches of the Thames between Henley and Dartford. Each of these benches indicates a phase of low sea-level, i. e. a phase of climate colder than the present.

G: Swanscombe bench of Antepenultimate Glaciation 2 on which the Hornchurch boulder clay lies (probably equivalent of Elster Glaciation of Germany).

N: Taplow bench of Penultimate Glaciation 2 (probably Saale Glaciation of Germany).

This is followed by 5 benches of which the lowest 3 are the buried channel benches P, Q and R as indicated in Table 1, which correspond to the three phases of the Last Glaciation.

Now,

the l o w e r of t h e s e a g g r a d a t i o n s rests on a rock bench w h i c h has b e e n

identified over s o m e d i s t a n c e a l o n g the course of the r i v e r (fig. 2 ) . It is f o l l o w e d by

t h r e e m o r e rock benches all c o n t i n u i n g to a l o w s e a - l e v e l , the last b e i n g f o l ­

l o w e d b y the rise of the s e a - l e v e l u p to its p r e s e n t - d a y height. T h e s e are the w e l l k n o w n „ b u r i e d channel benches". T h a t there are three, confirms t h e o b s e r v a t i o n m a d e e l s e w h e r e that t h e L a s t G l a c i a t i o n h a d three cold phases. B u t t h e terraces of the T h a m e s p r o v i d e additional i n f o r m a t i o n of g r e a t interest. T h e a g g r a d a t i o n w h i c h rests on the first of t h e three b u r i e d channel benches constitutes t h e L o w e r F l o o d P l a i n T e r r a c e w h i c h a l w a y s r e m a i n s a f e w feet a b o v e the m o d e r n flood piain. T h i s stage, the H a i l i n g S t a g e of K I N G & O A K L E Y ( 1 9 3 6 ) , occasionally also

Riss or W ü r m ?

101

called the Eyot Phase, indicates a sea-level at a height of something like 3 m a b o v e the present, though because of the inevitable e r r o r of measurement and the tidal amplitude an e x a c t figure cannot at present b e g i v e n . The fact that the sea-level rose as high as this suggests that the climate o f this phase was temperate.

T h e Hailing stage was f o l l o w e d by t w o c o l d phases separated b y a less cold interval (Ponders E n d aggradation) during w h i c h the sea-level n e v e r rose to the present height ( Z E U N E R 1945, p. 130).

This evidence f r o m the L o w e r Thames suggests that following the t w o M o n a ­ stirian sea-levels, three cold phases occurred. T h e first and second o f these w e r e separated by a m i l d phase as temperate as the present day climate, in other w o r d s , cf a fully interglacial character. T h e oscillation b e t w e e n the second and third, h o w e v e r , never led to a deglaciation c o m p a r a b l e w i t h that of the Postglacial. It is unlikely, therefore, that during this second m i l d phase the climate assumed a temperate character.

A s a fossil shore-line, the Hailing stage has b e e n found in a large n u m b e r of places o n the south coast of western England. Its transgression platform occurs at L a n n a c o m b e (South Devon) f o r instance, w h e r e it is covered with thick soli­ fluction deposits p r o v i n g that this level cannot b e o f Postglacial age. It also occurs in Jersey (Channel Islands), at Gibraltar, A r a b ' s Gulf (west of A l e x a n d r i a ) , the Atlantic coast of M o r o c c o and elsewhere (ZEUNER 1953).

T h e climatic sequence supplied b y this e v i d e n c e , therefore is as follows: — 1) T w o phases o f the Penultimate Glaciation.

2) T h e Last Interglacial, w i t h t w o w a r m phases represented b y sea-levels at 18 and 7.5 m a b o v e the present and separated b y a slight oscillation.

T h e w a r m character of these t w o phases is e v i d e n c e d b y their Strovibus fauna in the Mediterranean which corresponds to the E e m fauna of the North Sea. 3) A cold phase with l o w sea-level.

4) T h e Hailing phase with sea-level rising t o about 3 m a b o v e the present, of a temperate character.

5) T w o cold phases separated b y an oscillation during which the sea-level remained b e l o w present height and the climate o f which never b e c a m e typically temperate.

6) T h e Postglacial.

T u r i n g n o w to the loess belt, it is remarkable that the same sequence of c l i m a t i ; phases is exhibited b y the Y o u n g e r Loesses, t h o u g h not e v e r y w h e r e . Three Y o u n ­ ger Loesses have b e e n established in the Mainz basin, in Alsace, in Czechoslovakia and in L o w e r Austria. T o find them, therefore, it appears that o n e has to g o t o areas w h e r e the s u m m e r is comparatively w a r m e r and w h e r e the climate has continental tendencies. Farther west, especially in France, the Third Y o u n g e r Loess appears to b e absent, which is not surprising, since during that last phase of the Last Glaciation, which w a s the weakest of the three, the influence of the o c e a n m a d e itself most strongly felt. The division b e t w e e n the S e c o n d and Third phases o f the Last Glaciation, h o w e v e r , is e v i d e n c e d b y soils o c c u r i n g b e t w e e n solifluction levels in several French sites, as it is, incidentally, at the Petersfels in southern G e r m a n y .

T h e evidence f r o m the Mainz Basin has b e e n studied b y S C H Ö N H A L S (1950, 1951a, b ) from the pedological point of v i e w . W h i l s t the Last Interglacial soil is usually a chernozem, the soil b e t w e e n the First and Second Y o u n g e r Loesses is a brownearth. Similarly the soil between the S e c o n d and Third Y o u n g e r Loesses has b r o w n e a r t h characteristics, b u t it is thinner a n d less deeply weathered.

A t the prehistoric site of Achenheim situated o n the French side of the southern Rhine Rift, the presence of the three Y o u n g e r Loesses has been suggested on t h e

STAGE THIRD BURIED C H A N N E L (R)

LOWER AUSTRIA

BRAUNERDE

WEATHERING

JÜNGERER L O S S III

YOUNGER LOESS III

BRAUNERDE

PAUDORF PHASE

ALPS

PREHISTORIC INDUSTRIES

WEATHERING

MESOLITHIC

C.

— 30 M .

G L . 2/3

C

— 10 M .

PONDERS END AGGRADATION

LAST GLACIATION

C

— 70 M .

SECOND (PONDERS END) BURIED C H A N N E L (Q)

LOESS RECENT II

JÜNGERER L Ö S S II

YOUNGER LOESS II

HALUNG STAGE, LOWER FL00DPLAIN TERRACE

SOL

BRAUNERDE

GÖTTWEIGER PHASE

TEMPERATE PHASE

FIRST (HEDGE L A N E ) BURIED C H A N N E L (P)

LOESS RECENT I

YOUNGER LOESS I

"JUNGRISS"

G L . 1/2

LAST INTERGLACIAL

LAST GLACIATION 1

EPIMONASTIRIAN + 3 M.

C.

— 100 M .

TEMPERATE

LATE MONASTIRIAN + 7-5 M .

UPPER FLOODPLAIN TERRACE

COOL

LOWER

BENCH O

TEMPERATE

MAIN MONASTIRIAN + 18 M .

TAPLOW TERRACE AGGRADATION

PENULTIMATE GLACIATION

C.

— 200 M .

TAPLOW B E N C H (N)

WÜRM

MAGDALENIAN

MAGDALENIAN

AURIGNACIAN GRAVETTIAN M0USTERIAN

JÜNGERER LÖSS I

LOESS ANCIEN (PART)

ÄLTERER

TABLE 1

LAST INTERGLACIAL

L.

DEEP WEATHERING

2

SCHWARZERDE

L.

ARGILE ROUGE

3

LÖSS

OLDER

LOESS

RISS

BEING REPLACED BY UPPER PALAEOLITHIC

MOU

STERIAN

ACHEUL.

LAST GLACIATION

TILBURY

L O E S S OF MAINZ BASIN

TAYACIAN

FLANDRIAN

THAMES

LOESS OF North FRANCE

MICOQUIAN & UP.

POSTG-LACIAL

LOWER

LEVALLOISIAN

SEA-LEVELS

FORMATION DE SOL

GENERAL NOMEN­ CLATURE

LEVALLOISIAN

Riss or W ü r m ?

103

evidence o f mechanical analysis b y D E F E R R I E R E and confirmed b y the writer.

A g a i n the u p p e r intermediate soil is w e a k e r than the l o w e r .

In B o h e m i a and M o r a v i a a number o f sections with three Y o u n g e r Loesses have been described b y L A I S ( 1 9 5 1 ) and S C H Ö N H A L S ( 1 9 5 1 ) . O n e of these is Sedlec, near Prague, another D o l n i Vestonice in M o r a v i a . The w o r k o f L A I S (his m a n u s ­ cript was c o m p l e t e d in 1 9 4 4 ) inspired B R A N D T N E R ( 1 9 5 0 ) t o search for similar evidence i n L o w e r Austria, w h e r e the soil b e t w e e n Y o u n g e r Loesses I and II is called the G ö t t w e i g e r l o a m o r Hollabrunner humus zone, whilst that b e t w e e n Y o u n g e r Loesses II and III is k n o w n as t h e P a u d o r f horizon. These names w e r e coined b y B A Y E R and G Ö T Z I N G E R some t w e n t y years ago, w h i c h shows that the evidence w a s there and o n l y waiting to b e c o r r e c t l y interpreted. L A I S , SCHÖNHAI.S and B R A N D T N E R agree in regarding the t e m p e r a t e period b e t w e e n Y o u n g e r Loesses I and II as l o n g e r than that between Y o u n g e r Loesses II and III. Pollen-analytical evidence has defined the difference b e t w e e n the t w o interstadials still further ( B R A N D T N E R 1 9 4 9 , 1 9 5 0 , p . 1 0 4 ) . The First Interstadial has s o far yielded pine, spruce, birch, willow, alder, hazel, elm, o a k a n d lime. This is an association representing a fully d e v e l o p e d temperate forest. In samples from the P a u d o r f horizon, h o w e v e r , the m o r e o r less cold-resisting species dominate, whilst the climatically m o r e sensitive like hazel, e l m and oak appear m o r e sporadically and the most w a r m t h requiring species, lime, is absent altogether. Moreover, density of the forest i n the G ö t t w e i g e r Interstadial w a s greater (herbaceous and grass pollen about 1 0 0 % ) than in the Paudorf Interstadial (non-tree pollen nearly 3 0 0 % ) .

This e v i d e n c e from t h e Mainz Basin a n d Rhine Rift, Czechoslavakia a n d L o w e r Austria proves that t h e three cold phases which f o l l o w e d the Last Inter­ glacial w e r e separated b y t w o interstadials, the first of which w a s fully temperate, whilst the s e c o n d did not attain such condition, except possibly for a brief period not n o r m a l l y recorded in geological e v i d e n c e . T h e r e is plenty o f other pedological evidence which supports this conclusion, especially regarding the cool character of

the S e c o n d Interstadial ( Z E U N E R 1 9 5 3 ) .

M o r e o v e r , w h e r e exposed, the soil o f t h e temperate phase preceding the f o r ­ mation of the Three Y o u n g e r Loesses is thicker than any o f the soils that f o l l o w and tends t o b e climatically somewhat w a r m e r than that between Y o u n g e r Loesses I and II. In northern France, this Last Interglacial soil is well k n o w n as a r g i l e r o u g e , because of its slightly reddish colour indicating temperatures s o m e w h a t h i g h e r than the present. Soils o f this type are n o w formed i n the brownearth zone south o f t h e Loire, b u t n o t in north F r a n c e where a r g i l e r o u g e is c o m m o n in the basins of the S o m m e and Seine. In southern England, similar conditions appear t o have prevailed as suggested b y the Last Interglacial soil of Ebbsfleet, Kent (ZEUNER 1945, p . 1 2 8 ) . In the Mainz Basin, the a r g i l e r o u g e is replaced b y a w e l l developed chernozem ( S C H Ö N H A L S 1 9 5 1 ) which is consistent w i t h the continental character o f this area. This evidence suggests that the „ w a r m " character of the Last Interglacial was in the main due to elevated s u m m e r temperatures as distinct from a h i g h e r annual mean.

N o w , it must b e admitted that t h e agreement of the climatic succession deduced independently f r o m the sea-level fluctuations on the one hand and f r o m weathering horizons on the other, is so c l o s e that it cannot b e ascribed to mere coincidence. F o l l o w i n g the Penultimate Glaciation, both sequences p r o v i d e f o r a Last Interglacial w i t h temperatures s o m e w h a t higher a cold phase, a period of fully temperate climate, another c o l d phase,

than present,

104

F. E. Zeuner

a p e r i o d with climate o n l y moderately temperate, a third cold phase, f o l l o w e d by the Late Glacial and Postglacial.

F r o m the point of v i e w o f nomenclature, the longest and warmest p e r i o d should be regarded as the Last Interglacial. T h e three cold phases that f o l l o w w o u l d then represent the three phases of the Last Glaciation which have b e e n recognised b y m a n y workers in the A l p i n e and periglacial areas.

A v e r y remarkable feature, h o w e v e r , is n o w emerging. T h e interstadial b e t ­ ween the first and second phases of the Last Glaciation w a s fully temperate.

Though shorter than the Last Interglacial, it w a s quite as temperate as the P o s t ­ glacial. If, therefore, deposits belonging to the First Interstadial of the Last Glaciation are found unassociated with formations of the Last Interglacial, such deposits w i l l automatically b e interpreted as Last Interglacial b y most authors.

Evidently the distinction b e t w e e n formations of the Last Interglacial and the First Interstadial is a difficult matter unless exceptionally c o m p l e t e sections are available. T o m a k e matters e v e n m o r e difficult, deposits of the First Interstadial of the Last Glaciation are likely to b e p r e s e r v e d frequently, since they are y o u n g e r than those of the Last Interglacial. In m a n y districts, therefore, it m u s t be considered as a serious possibility that e v i d e n c e for the First Interstadial has been misinterpreted as Last Interglacial.

The facts briefly discussed in this paper t h r o w fresh light on the question o f what s h o u l d b e regarded as Riss and as W ü r m respectively in the Alpine area o f glaciation. In recent years s o m e investigators h a v e c o m m e n c e d to use the t e r m „Jungriss" for a glacial phase which they f o u n d to b e comparatively well s e p a r a ­ ted from the later c o m p l e x of W ü r m moraines. It n o w appears likely that this is the phase Last Glaciation I of the general nomenclature, its clear separation being due to the temperate interstadial L G I 1 / 2 . Since, h o w e v e r , the mild p e r i o d preceding the cold phase in question is k n o w n to have b e e n longer and w a r m e r than L G I 1 / 2 , it is inadvisable to transfer the term Last Interglacial to L G I 1 / 2 .

A great deal of confusion w o u l d thus be caused. Whilst, to the best of m y k n o w ­ ledge, n o b o d y has yet suggested this in so m a n y words, it is unfortunately i m p l i e d in the use of the term J u n g r i s s . Geologists not acquainted with the p r o b l e m would inevitably take J u n g r i s s to mean that this phase was in time m o r e closely linked with the Riss Glaciation and that it was f o l l o w e d by the m a i n Last Interglacial. What has happened is, of course, merely that a glacial phase, the equivalent of which in the periglacial z o n e has often b e e n called W ü r m I, has n o w p r o v e d to be well separated from the Alpine W ü r m complex, t h o u g h even so it is closer to the W ü r m than to the Riss complex. There appears to b e little enthusiasm among A l p i n e geologists f o r continuing to call this phase W ü r m I, a term preferable to J u n g r i s s . T h e best w a y out may w e l l p r o v e to be the introduction of a c o m p l e t e l y n e w n a m e . The attached table is intended to summarize the evidence as it stands, in the hope that it m a y prove useful as a basis for discussion of the nomenclatorial p r o b l e m . A s to the facts, I h a v e the impression that a large measure of agreement already exists among the i n ­ vestigators concerned, though local details remain to be w o r k e d out.

References BRANDTNER, F . , 1 9 4 9 . Die bisherigen Ergebnisse der stratigraphisch-pollenanalytischen Untersuchung eines jungeiszeitlichen Moores von interstadialem Charakter aus der Umgebung von Melk a. Donau, N . - ö . - Archaeol. Austriaca, Wien, 2, pp. 5 - 3 2 . - - 1 9 5 0 . Über die relative Chronologie des jüngeren Pleistozäns Niederösterreichs. - Archaeol. Austriaca, Wien, 2, pp. 1 0 1 - 1 1 3 . .

Riss or W ü r m ?

105

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KING, W. B. R. & OAKLEY, K. P., 1936. The Pleistocene Succession in the Lower Part of the Thames Valley. - Proc. prehist. Soc. (n. s.) 2, pp. 52-76.

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ZEUNER, F. E., 1945. The Pleistocene Period. Its Climate, Chronology and Faunal Suc­ cessions. - 322pp. London (Ray Society) (See pp. 127, 130). - - 1952. Dating the Past. - 3rd edit, 495pp., 24pls., London. (See pp. 158, 193). - - 1953 (a). Notes on the Stratigraphy of the Magdalenian. - Rep. Univ. London Inst. Archaeol. 9, pp. 10-28. - - 1953 (b). The three Monastirian shore- lines. - Proc. 4th I N Q U A Congr. Rome 1953 (in the press). - - 1954. Loess balls from the Lower Mousterian of Achenheim (Alsace). - J. R. anthrop. Inst. London 83 (in the press).

Manuskr. eingeg. 1. 2. 1954.

Anschrift des Verf.: Prof. Dr. F. E. Zeuner, Univ. of London, Institute of Archaeology, Inner Circle, Regent's Park, London N W 1.