on the cenozoic deposits of the lower huangho valley

ON THE CENOZOIC DEPOSITS OF THE

LOWER HUANGHO VALLEYt

B

M. N. Bi (11)Cenozoic Research Laborory, Geological Survey

introduction ....General Observations ...Descriptions of the Sections

I. TheSanmen Area .......... .........EL. The Melania Beds of Fenglingtu opposite Tungkuan

Age of the Melanin Beds ............. ..........Possible Cause of the Occurrence of Lower and Upper Series in the

Sanmenian Deposits ..........Conclusions

INTRODUCTION

The part of the Lower Huangho Valley with which this paper dealsis I)OUflded on the west by the T'ungkuan Bend where thç Loho (iuiJ) andthe Weiho ( iUJ) join their master stream and on the east by the SanmenRapids (r9ti). The area which lies between P'ingluhsien ),Shansi and thç Sanmen Rapids is arbitrarily designated as the Sanmen Area(figure 1 and map of Plate I).

Since the discovery of the type locality 0f the Sanmen formation by Dr.V. K. Tingt in 1918 about 9 Ii above the well known Sanmen Rapids whereabundant thick-shelled Unionids of the genera Lam protula and Cuneopsís werefound in the pre-Loessic fresh-water beds, subsequent discoveries especially by

1 Received for publication July I, 1934.

2 J. G. Anderason: Essays on the Cenozoic of North China. Mcm. Geol. Surv.China, Ser. A, No. 3. p. 118. 1923.

434 Bulletin of the Geological Society of China

Dr. J. G. Andersson3, Dr. G. B. Baibour4, P. Teilhard de Chardirt and P.E. Licent5 of pre-Leessic fresh-water deposits at different localities which bearsimilar thick-shelled Unionids were correlated with the Sannen type Localityand the term "Sanrnen" finally enjoyed the distinction of being the name ofthe pre-Loessic stratigraphical unit. Later development in the research on thepre-Loessic formations through the joint effort of P. Teithard de Chardin andDr. C. C. Young is best summanzed in the memoir on the Foi5il Man of Chinaedited by Dr. Davidson Blacks, the late Hon. Director of th CenozoicResearch Laboratory National Geological Survey of China.

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i: s00000025

Figure I. Index Map

3 Andersson, op. cit., p. I 19. - _______4 G. B. Barbour: Deposits of the Sangkanho Valley, Bull. Geol. 5o:. China.

Vol. 4. p. 53, 1925, Deposit and erosion in the Huailai Basin. Bull. Ceol, Soc.anna, Vo!. 5 p. 47, 1926.

5 Teilhard de Chardin and E. Ucent: Formations quaternaires et tertiaires superieuresdu Honan et du ausi. Bull. Geol. Soc. China, Vol. 6, 2, p. 129, 1927.

6 Davidson Black, Teithard de Chardin, C. C. Young and W. C. Pei: Fssil Manin China. Mein. Ceol. Sur,. China, Ser. A, No. 11, p. 50, 1933.

M. N. Bien: Cenozoic Deposits of Lower Hr*angho Valley 435

While our knowledge corerning the Cenozoic geology of North Chinahas progressed, the Sanmen type locality has not been revisited again until lastsummer (1933) when Dr. C. C. Young and Mr. W. C. Pei made a study onthe Cçnozoic geology between Loyang and Sin7, but unfortunately they wentin the flood season and the beds which bear abundant characteristic fossilUnionids of the genus L«n-protula were made inaccessible to them. Upon thesuggestion of Dr. W. H. Wong, Director of the Survey and Dr. V. K. Ting,Hon. Director of Cenozoic Research in China, who felt the need of a morethorough collection of fossil Unionids from the Samnen type locality for coin-parison in the forthcoming systematic study on the Cenozoic fresh-water mol-Iusks8, the writer had the opportunity of being sent into the field to the revisitthe Sanmen region by the Cenozoic . Research Laboratory and, at the sainetime, P. Teilhard de Chardin suggested the re-examination of the problematicMelania Beds of Fenglingtu (U) opposite T'ungkuan

The writer is indebted to Dr. V. K. Ting, P. Teilhard de Chardinand Dr. C. C. Young who kindly furnished him with valuable informationconcerning the above mentioned localities before he left for the field. onDecember 5, 1933

Gri. OBSERVATIONS

The highly aggraded condition of the Lower Huangho Valley hasalready attracted the attention of Willis, Teilhard, Licent1° and Barbour11.On both sides of the river, high fan-terraces of a hundred meters in height sweepdown from the southern slope of Chungtiaoshan (41* di) on the north and the

:7 C. C. Young and W. C. Pci: On the Cenozoic geology be.nveen Loyang andSian. Bull. Geol. Soc. China, Vol. 13, No. I, p. 73, 1933

B Dr. Davílson Black before his death, had kindly entrusted the writer the task ofstudying the Cenozoic f resh-watcr mollusks.

9 Bailey Willis: Research in China. Carnegie Inst. Washiigton Pub. 54, Vol.1,pt.l, p.225, 1907.

10 Teilhard and Ucent: op. cit.

II G. B. Barbour: Pleistocene History of the Huangho. Bull. Geol. Soc, America,Vo!. 44, p. 1150, 1933.

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M. N. Bien:Cenozo'ic Deposits of Lower Huangho Va,

half buried fault-scarps of the northern fronts oí T'aihuashananii

Yaoshan (M I-i-i) on the south with a remarkably regular tOpographjsurfacewhich incline gently toward the axis of this large, longitudinal basin, One

could see a depression roughly parallel to the present channel in the surfaceof the high fan-terrace distinctly from the west of T'ungkuan and notice:ththe present Huangho has not followed the depression but is flowing in a canybetween high loess-veneered bluffs to the south of the depression (figure 2).Another depression is observed in the surface of the high fan-tenace furtjidownstream to the east of Shenhsien but here the present stream isLodged in a similar canyon to the north of the depression (figure 3). At many

places the high fan-terraces descend with gentle escarpments, artificially ter-i'aced by industrious farmers, to the lower terraces of thirty meters or more inheight (figure 3, Pl. I, sections B and figs. 1 and 2, Pl. IV). Tenaces ofintermediate heights between the high fan-terraces and lower terraces which areevidently "swing tenaces" were seen to ocçur at different points along theriver. Both the high fan-terraces and the lower tenaces are matched featureson both banks and their surfaces are clearly 'depositional surfaces".

Flood plains are not well developed along this segment of the Huangho,though the. one on which the city 0f Pingluhsien lies is of considerable area.As the present stream is dominantly degrading in this region, the earlier floodplains o the present cycle are left out of reach of even the highest floods. Theyare extensively utilized by the farmçrs there for the cultivation of fruit trees.

Below T'ungkuan, after changing abruptly from a north-south course,the Huangho flows eastward and then northeastward cutting in the soft andlocally consolidated late Cenozoic deposits which form imposing terraces by

12 This depression and another on the south bank 15 miles downstream between Wen-hsiang and Lingpao have already been observed by Barbour. According to him,they cannot be explained as ordinary meander cut-offs nor as later tectonic effectsand, furthermore, the present stream does not follow the axes of these depressions,remains the unexplained feature which may need careful topographic mappingin order to settle the point. Barbour: Pleistocene History of the Huangho, p.1151

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M. N. Bien:Cenozoic Deposits of Lower Huangho Valley 439

the sides until it reaches the Eocene gypsiferous arça where it is working inthe more consolidated and tilted Eocenc beds, and entrenching in a truc rockygorge in the hard Carbonilerous strata and the associated intrusives at Sanmen

(F) (Pl. Il, fig. I). Here the river makes two right-angled bends within.a distance of one kilometer between them on account of the resistant igneousmass which gives rise to the well known rapids. The river has cut three chan-nels, which the name Sanmen Çfhree Gates) signifies, in the mass of micro-granitic rock that is irregularly jointed, leaving isolated blocks standing in theriver. The southernmost block is called "Tichu" (it), because it standslike a pillar in the river. A boat was seen descending the river by shootingthe rapids of the middle channel and then letting the current cany it aroundthis rock, in the manner described by F. G. CIa'4.

The minor rapids south-east of Huangtweitsun (#) about five'kiilomecers above Samnen are caused by the indurated Sanmenian sandstones(Pl. Il, figs. 2 and 3). Although these minor rapids are not dangerous toascending traffic, yet a loaded boat needs more than ten trackers to toW itupstream. Tle sandstone ledges in the river bed actually stand from less thanone to four meters above the river level at low stage which prevailed whenthe writer was there, and some of them were seen to possess miniature pot-holesof not more than one meter in diameter and depth, with pebbles on their bot-toms. They are apparently caused by the eddies generated by the uneven bot-tom during high water.

DEScRIFFIoNs oi THE SECTIONS

I. THE SANMEN AREA

The Sanmen area lies immediately above the Sanznen Rapids. Goodsections are exposed by the vertical faces of the terraces which flank the riverand also by the walls of the lateral gullies. The horizontal and vertical dis-

13 S. L. Tsao: Gypsum of P'io Lu district, South Shansi. Bull. 5oe. ina, Vol.8, No. 4, p. 327, 1929; Young and Peî: op. dt., p. 78.

!4 F. G. Ciapp: The Huai'igho. Cicog. Rev., V01. 12. p. 14, 1922.

440 Rulletin of the Geologicd Society of China

tributions of hard rocks and superficial deposits are shown in the geologícalsketch map and schematic sections (A, B) of Plate I respectively.

L Hard rocks

Black shales and dark grey sandstones of the Carboniferous coal series(C), dipping northwestward with an angle of about 15', are exposed alongthe left bank of the Huangho at Sanmen where the river narrows and entersthe hills. This coal series is intruded by microgranite (G), which is respon-sible for the Sanmen Rapids.

2. Superficial deposits

Eocene gypsiferous deposits (E).

Along the river, the chocolate and red colored lower conglomeratic andcoarse sandy zone and a part of the gypsum-bearing middle clayish zone of theEocene gypsiferous deposits (E) are exposed. The deposits are strongly tiltedand dip about 25 to north-northwest. They rest unconforinably upon theCarboniferous coal series (C).

Sanmen Lower Series

The clay and sandy facies of this fresh-water series, most probablylacustrine in origin, vary from place to place, and west of Maotsirigtu ( tP

), this series is represented only by laminated clay of varying colors rangingfrom red, orange to green, with sandier intercalations. The exact thickness ofthis series is verj hard to tell, because the present Huangho is apparently stillcutting into the lower members of this series without exposing any older de-posits or the underlying bedrock from the T'ungkuan bend downstream to a fewkilometers above the Sanmen Rapids where this series comes to rest against the

Eocene gypsiferous deposits (E). For this region, this series is arbitrarily

divided into (i) Lower Clay (LC), (ii) Cross-B ethied Sand (CS), and (iii) Upper

Clay (UC).

(i) Lower Clay (LC). Horizontal layers of brown and buff coloredclay with sandy intercalations exposed only by the vertical face of the lwer

M. N. f3ien:Ccnozoic Deposits of Lozoer J-luangho Valley 441

te;rrace below the village Tungyen (44). Abundant big bivalves and alsoyoung individuals of the genus Lain protula were collected from this horizon.tvlany adult specimens were found with their valves intact and standing edge..

wise as in living condition. Associated with these bivalves, several forms ofplant leaves; some fresh-water snails (Melanja1, Lymna, and Planorbis); seveÉalland snails (Helicids); fish remains as isolated phaiyngeal teeth (Cyprinus,Cieno pharyngodon and Hypophfhdmichthys), vertebr and spines; and a fewindeterminable mammalian remains were found.

(ii) Cross-bedded Sand (CS). Beds of sand with interbedded gravel

layers which dip with varying degrees from 8' to 18' upstream were seen tohave their upper ends truncated by beds of similar nature dipping in the oppositedirection. Only the sections along the river show this cross-bedded characterclearly, while in a north-south section (e.g. Tungkou the apparent dipsof these sandy beds are less pronounced. This type of cross-bedding of rda-tivdy large dimensions suggests that the beds may be the coalesced f oresets ofan irregular lobate delta of a stream which emptied into a lake with the LowerClay (LC) as part of the buried bottomsets; or they may have been caused bythe configuration of the basin in which they were laid as the irregular filling ofhollows, or the irregular shifting of sandbars. Some of the beds are so stronglymdurated that the term sandstone15 could be safely applied to them and they areresistant enough to give rise to the minor rapids southeast of Huangtweitsun!The agent of cementation is calcium carbonate's.

Fossils were found a three different places under different conditions:

The compact sand above the Lower Clay (LC) yielded shells ofLarnprotula and one right valve of a huge (21 cm. in length and 15 cm. inheight) and moderately thick-shelled Unionid.

In the gravel layer of the indurated sandstone at the mouth ofHuangtweihokou (iJt), a complete left costal bone of a large Triony-

15 The hard sandstone at Lingpao mentioned by Teilhard and Licent which diptowards SSW may be of the same origin. Teilharcl and Licent: op. cit., p. 131.

16 The sandstone specimens were kindly analyzed by Mr. S. C. Liang of the Depart-ment of Mineralogy of the Survey.

442 Bulletin of the Geological Society of Chirus

chid; remains of hard-shelled turtle; fragmentary lower jaw and canon bone of asmall deer; and a large humerus of an Attiodactyle were found.

3. About one li below Huangtweihokou, the relatively loose sandbetween two layers of strongly indurated sand yielded a few shells of Lampro-tila and a foot-bone of a Proboscidean (Elephas?).

(iii) Upper Clay (UC). Horizontally laminated clay of uniform green-ish-grey color with occasional small lenses of coarse yellowish sand towards thetop. The Upper Clay (UC) and also the Cross-Bedded Sand (CS) arc some-what eroded by the stream that deposited the overlying series. Below Tung..yen, the writer collected the tip of an antler of deer and several shells ofLam prolu)a in one of the sandy lenses.

Sanmen Upper Series

This fluvial series ranges from 10 to 20 meters in thickness and consistsof gravel (MG) overlain by sand (US), sometimes with lateral facies of cia?'.The Sar.men Upper Series rests disconformably over the Lower Series and inthe Eocene area it overlaps the Eoccne deposits and rests unconformably uponthem. fhe Components of the Middle Gravel (MG) consists of metamorphosedrocks, vein quartz, and w athered igneous rocks in pebbles of varying sizes which

seldon exceed 60 mm. in diameter. lt passes laterally, away from the presentHuangho, into granule-gravel lenses sometimes intercalated with a strongly con-solidated layer of coarse sand'8. Several internal and external casts ofP!anorbis, Lam protula, and a Helicid; some external moulds of L«mproul;one right costal bone of a hard-shelled turtle and a scapula of an Artiodactylewere found in this hardened layer in Tungkou. The Upper Sand (US) isyellowish in color, coarse below and getting finer towards the top. The fine

17 The writer considers the "marty and sandy clay, lying on a basal cong-

lomerate and passing at the top ¡rito true reddish loam (r)" described by Youngand Pci (op. cit., p. 74, fig. I) as the lateral facies of Upper Sand (US) and thebasal conglomerate which is also called "gravels b" as the Middle Gravel (MG).

18 According to Dr. C. C. Young, the moderately consolidated fossiliferous coarsesand from which he collected the two isolated teeth of Mirnornys corresponds tothis layer. Young and Pei: op. cit., p. 77.


sand is sometimes thinly bedded. Some fragments of Lamprotula shells; ahypoplastnn ot a hardshelled turtle; a part of an antler; and one larnellaof a Prohoscidean's molar (Ele phas?) were collected from this zone.

Reddish loam (r).

The Upper Sand (US) is overlain by Reddish Loam (r)" whichthickens towards the mountains, attaining a thickness of 50 meters or more withbanded layers of concretions exposed towards the top. In some erosion pipesof the Reddish Loam, the writer has noticed a layer of gravel of 2-3 metersthick underlying the loam above the Upper Sand (US) suggesting disconformity,but the gravel might be locally developed, still belonging to the Sanmen Upper

Series. As no fossils were found, this loam is tentatively regarded as Chou-koutien in age, because Young and Pci2° believed that, at least along theHtuangho valley to the west of 'the Eocene gypsiferous deposits, there is noreddish loam of Nihowan (Sanmen) age developed, and furthermore, as they

say, "between these two later barns (Sanmen and Choukoutien), the boundary,it must be confessed, is still generally very difficult to draw." At the sametime, it is not impossible to say that both barns are present.

Loess (L).The loess lies on all hoizons of the older deposits with or without

basal gravels.

Alluvium (A).Heterogenous mass of materials retaken from the older deposits which

fonn the lowest 8-10 meter terraces etched out by the Huangho and its lateralstveams which are dominantly erosional at present.

Il THE MELANIA BEDS 0F FENGLINCTU OPPOSITE T'UNGKUAN

The section of figure 4 shows the succession of deposits which com-posed the high bluff of Fenglingtu that faces T'ungkuan. The southern face

19 At many places the Reddish Loanis (r) were seen to rest upon the Upper Sand (US)

with a sharp contact indicating that the change from the sandy to loamy facies is

very abrupt,20 Young and Pci: op. cit., p. 81 and p. 86

444 Bulletin of the Geological Sociefy of China

of this bluff has suffered from small land-slips which marred the true succes-sion of beds, but fortunately the western side has not been disturbed. Thedetails of this section could be given thus:

Mdania Clay. An alternation of pink and green horizontallylaminated clay with sandier intercalations that bear remarkably regular layers offine sandy concretions. At places, they are overlain or underlain by indurated

lenses of sand. The pink and green clay yielded abundant fragile fresh-watergastropod shells of the genus Mçlania associated with some land snail- shells(HelicidsL fish vertebr and an incisor of a small rodent.

Figure 4. Section of the high bluff of Fenglingtu.

Lamprohila Sand and Gravel. Overlying the Melama Clay, thereis a layer of gravel which slopes northward. The components of the gravelare igneous and metamorphosed rocks, sandstone, vein quartz, etc. in pebblesof different sizes. At the southern portion cf the section, the components ofthe gravel are of such size that it might be termed "boulder gravel", whiletowards the north, they are distinctly finer and the gravel could be termed"pebble gravel." Shells of Lamprofula and Cuneopsis were collected fromthe pebble gravel. The gravel is followed by stratified loose yellowish sand,from which a few shells of Corbicula; some fragments of Lamprotula shells;and some mammalian remains such as the vertebra of a Proboscidean (Ele phas ?),the burr and tip of antler of a deer, the splinter bone of a horse, and thephalanx of a Carnivore were collected in situ. A fragmentary lowet jaw ofEuryceros pachyosteus, a typical Choukoutien form, distincdy rolled, was pickedup on the slope.

M. N. Bien:Cenozoic Deposite of Lower Huarigho Valley 445

3. Loess. The older deposits are capped with loess 0f varying thick-

ness.On the T'ungkuan side of the Huangho, the succession of deposits is

essentialy the same, but the pink and green clay is devoid of fossils.

AGE OF THE MELANIA BEDS

The M ei unja Beds have been regarded at first to be older than Pontianin age by Andersson21, and later by Teilhard and Licent as Pontian, thoughthey also mentioned that it is not impossible to regard them as a facies of theSanmen Beds. Because of (1) the occurrence of Meiania of the same typeassociated with Lam prolula in the Sanmen Lower Series of the Sanmen Area;(2) the similarity in lithology such as the relatively advanced state of con-solidation and the fine lamination of clay elements; and (3) the same basalposition in the stratigraphical sejuence of being still cut into by the presentHuangho and overlain by gravel and sand (Saninen Upper Series) which stillbear fossil Lamprolula, the writer considers the Melania Beds to be contempor-aneous with the Sanmen Lower Series of the Sanmen Area, or in more generalterm, they are a part of the Sanmen Lower Series of this part of the LowerHuangho valley.

The association 0f Euryceros pachyo'sf eus with Lampro fula Sand israther disconcerting, but we may suppose that the remains of the animal, so farunkiown in the Lower Sanmenian, have been rewashed from some destroyedloam, and become embedded in the top of the Laniprotula Sand at the begin-

ning of the Loess deposition. Another hypothesis would be to admit that theupper part oI the so-called Lamprotula Sand actually corresponds to a fluvialfacies of the Choukoutien loam.

POSSIBLE CAUSE OF THE OCCURRENCE OF LOWER AND UPPER SERIES

IN THE SANMENIAN DEPOSITS

The significant fact of the perched positions of the Sanmenian beds

al ong the Shensi-Shansi H uangho gorges above the Lungmen ( i') straits

21 Mentioned in the footnote of Teilhard and Licent's naper: op. cit., p. 122; inthe text of Young and Pci's paper: op. cit., p. 8!

22 Teilhard and Licent: op. cit., p. 133.


and the occurrence of the same beds in the very bottom of the valley furtherdownstream and east of T'ungkuan has repeatedly been emphasized by previousinvestigators. The relationship has generally been attributed to the unequallydistributed effects of late vertical movement, though the possibilities of regrading

as the result of capturez and of lowering of base-level by strandline shif tu havealso been suggested. Bearing these possibilities in mind, it is worthwhile,perhaps, attempting to reconstruct the condition which led to the deposition ofthe Sanmenian beds. In so doing, it should not be forgotten that at the pre-sent stage any such reconstruction can only be in the nature of a workinghypothesis, to be checked and recorsidered carefully in the light of futurefindings.

Let us suppose that when the region athwart the Huangho valley be-tween Shensi and Shansi was slowly uplifted by the Fertho warping begin-

ning from Middle Pliocene time, this area was subsiding along the old line ofweakness made by the eastern extension of the Huaying-Lint'ung fault of theTsinlingshan and stood somewhat lower with reference to base-level than theEocene area further east which was left higher. This resulted in the pondiñgof the river and the valley here was starting to be filled with lake-laid sedimentswhile the upper reach of the river continued to degrade its bed. When theiflowing stream was at grade with the temporary base-level established by thelake, it started to deposit, but this condition of equilibrium was not of longduration before the river began to degrade again. Meanwhile the outlet ofthe lake at some point to the east, presumably on the relatively softer Eocenodeposits, had its overflow level slowly reduced while the surface of the lake-

23 Teilhaid de Chardin and C. C. Young: Pre-Loessic and Post-Pontian forma-tions in W. Shansi and N. Shensi. Mem Geol, Serv. China, Ser. A, No. 8,p. 30; C. Y. Hsieh: Note on Geomorphofogy of North Shensi Basin. Bull.Geol. Soc. China, Vol. 12, No. 2, p. 192; G. B. Barbour: op. cit., 1933,

p. 1155; Young and Pci: op. cit., p. 88.24 Teilbard and Young: op. cit.25 Hsieh: op. cit.26 G. B. Barbour: op. cit., 1933, p. f155.27 Mcm. GeoL Surv. China, Ser. A, No. 9, p. f87, 1931.


laid sediments was gradually raised through silting. This consequently ledt the draining 0f the lake. As soon as the lake was drained the deposit be-came purely fluviaL was therefore liable to settle at any point in the valleybottom. It is not therefore to be expected that the area over which it occurredwould be co-extensive with the original limits of the ponded area; instead itformed an alluvial layer extending as far downstream as the river could carryit. As a result of this aggradation the entire bedrock floor was buried andceased to exercise any control on the main channel. During the succeedingrejuvenation the river, having swung laterally to a new position, found itselfcutting indifferently down into thc top of the bedrock barrier which had beensubmerged in the preceding epoch. Having now a gradient sufficient to en-courage the persistence of vertical cutting it continued to degrade its channelin the rocky gap which to-day forms the gateway of the Sanmen. The unequalresistance of the bedrock structures, especially the lines of weakness afforded

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Figure 5. Comparison of Huangho Sections A, near Hoshan (after Teilhar'd and Young)and B, of Tungyen.

by prominent jointing, led to a development of three channels which remainseperated through the failure of the river to undermine the rock islands whichdivide its waters.

A history of this kind will explain the marked contrast in the structurairelationships of the three types of deposits, in the two localities under dis-cussion, of which diagrammatic sections are here figured (see figure 5) for com


parison. The continued upwarps would account for the progressive elevationof the old deposits, while the subsidence postulated for the area this paperdealt with %yo1ld explain their normal order of superposition. With a mo-dification of the hypothesis by inserting the late Pliocene faulting found in theTaiku area28, the structural relationships of the Fenho could be similarly accountedfor and it is believed that corresponding modifications will prove equally satis-factory in explaining the observation for the 'Weiho and the minor tributariesof this drainage system.

As stated above, this interpretation is by no means conclusive andshould be regarded as a working hypothesis, but it is hoped that it would beof use to future investigators.

CONCLUSIONS

In the Lower Huangho Valley, there occur two freshwater series inthe Sanrnen formation: (1), a Lower Series of lake-laid beds which restsagainst the Eocene beds of P'ingluhsien and, (2), an Upper Series cf fluvialbeds which overlaps the Eocene deposits. The Melania Beds of Fenglingtubelong to the Lower Series. The age for the reddish loam which followsthe Upper Series is not certain and can only be fixed by an analysis of itspalontological contents.

28 C. B. Barbour: The Taiku deposits and the proUein of Pleistocene climates.Bull, Cool. Soc. China, VoL. X, p. 71, 1931.

Explanation of

Plate II.

449

PLATE 11

Figure 1. - Looking upstream from the Sanmen Rapids. T, Tayuiniao;C, Carboniferous strata; E, Eocene deposits; P, late Cenozoicdeposits; and G, micro-granitic intrusives.

Figure 2. - Minor rapids southeast of Huangtweitsun. Showing theSandstone ledge of indurated Sanmenian sand in the rives bed.

Figure 3. - Part of the minor rapids. CS, Cross-bedded Sand; US,Upper Clay; MG, Middle Gravel; US, Upper Sand; andL, Loess.

450

M. N. Bien:Cenozoic Deposits of Lower Huangho Valley Plate II:

Explanation of

Plate III.

45 I

PLATE ill

Figure 1. - Showing the indurated Sanmenian Cross-bedded Sind (CS),in which Mammalian remains were found, overlain by alluvium(A).

Figure 2. - Section exposed by the vertical face of the Lofler Terracebelow Tungyen. LC, Lower Clay; CS, Cross-bedded Sand;MG, Middle Gravel; US, Upper Sand; and L, Loess.

Figure 3. - Nearer view of section shown in figure 2.

452

-9

M. N. Bien :Cenozoic Deposits oj Lower Huanglio Valley Plate 1111

Explanation of

Plate IV.

453

PLATE IV

Figure 1 - Dissected High Fan-terrace behind the village Tungyen.Looking towards north. r, Reddish Loam with banded layersof concretions; and L, Loess

Figurt. 2. - Deeply incised Lower terrace. Taken from the same point asthat of figure 1. The gully to the left of the reader is Tungkou.

Figure 3. - Western face of the bluff to the north-west of Fenglingtu.Technician Wang is standing on the mud-flat. 1, Mdatta Clayoverlair. by a lens of consolidated sand; 2, Lamprotula Sandand Gravel; and 3, Loess.

454

M. N. Rien:Cenozoic Deposits of Lower Huanglio Valley Plate IV.

on the cenozoic deposits of the lower huangho valley

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