225

Appendix 1

Note on the Palynology of the Bombay Mangrove Swamps

In 1962 borings were carried out at Ghodbimder and by Professor Vishna>Hittre, but the pollen yield from these sites was poor (yishnu^Mlttre, personal communication). However, at his suggestion the writer resumed work In the area on the assumption that the new sites selected by him (at and Basseln; Fig.13) were In more protected tidal areas and less vulnerable to wave erosion. It was felt that If a pollen diagram could be constructed for the palaeovegetatlon In this area, an attempt could then be made to Integrate these results with a dated eustatlc curve (which project was already underway;

D.P.Agrawal, S.Kusumgar and the writer) and the available archaeological evidence. Regretably, pollen content from the writer's series of borings was also small and proved

Inadequate for the construction of a pollen diagram. It was therefore not possible to obtain a correlation of the palynologlcal, eustatlc and archaeological data. Nevertheless as the writer did undertake original research work In this field as a part of the Intended Interdisciplinary approach to the subject under consideration In this thesis, the findings are recorded below.

The map of Bombay (F ig .13) shows the rivers, creeks €Uid swamps mentioned In this section and gives the 226 location of the sites where borings were carried out by the writer.

The succession of mangroye plant communities in this area was described by Navalkar (1956) and has subsequently been slightly modified by the writer and

Dr. Vishnu-Mlttre as a result of their more recent obserrations. These are described below in a sequence moving landward from the coast.

i) Rhlzophora mucronata (Kandail. Kamo. Dumbi) ^ forms the community nearest the sea. It abuts the mud and sand along the creek at Ghodbunder and Bassein and it was observed that between 1956 and our observations in 1970 there has been considerable reduction in the number of these trees.

11) Avicennia alba (Tivar) stands on its own or with a few bushes of Avicennia officinalis and Acanthus illcifolius (Marandi) at several places, for example, at

Colaba and Madh Island, from to , south of

Chembur and at Ifadala. At other sites, for example, Hahim,

Ceriops candolleana (Klrrarl Chaurl) Brugulera gymnorhlza and Sonneratla apetela also occur, though rarely, in the « Avicennia community.

The terms in brackets are the local Marathi names for these mamgrove species. They have been listed only where available. They have been referred to in T, Cooke, 1903-8 and the Wealth of , 19^8 227

i i i ) Acaathtts lllclfolltts. where it does not grow mixed with Avicennia. fringes the latter.

iv) Aeluroptts villosus succeeds Acanthas. either as a pure distinguishable zone, or, as is more often the case, together with Suaeda fruiticosa (Morus UsaK Lani)

Sesuvium portulacastrum and Clerodendron inerme (Van.laal).

v) Clerodendron inerme forms a conspicuous belt along with grasses and sedges as one approaches dry soil and also grows well beyond the reach of the tide. It is a very common hedge plant in the Bombay area. The grasses include species of Sporobolus. Panicum (Varo^Vari) Paspalum

(Harik). Cyperus coiapressus. C. rotundas (Motha) . Flmbrlatvlls spp.

Stratigraphy

Cores were collected at various sites with a

Hiller-type sampler. The maximum depth penetrated was k m.

The stratigraphic sequence obtained from the 1962 borings was: O-75 cm of brown mud and 75-130 cm of dark blue-grey mud overlying the bedrock at ; and O-9O cm of brown mud, 90-150 cm of dark blue-grey mud and 150-510 cm of blue mud overlying bedrock at Ghodbunder (Vishnu-Mittre, pe rs onal communi cati on).

At Bassein, and Madh Island the brown mud varies in thickness from 25-80 cm, and the remainder of the profile consists only of blue-grey clay. Along the margins of the swamps, and in some cases even towards the centre, it was 228 quite common to strike bedrock at < 3 m depth. No horizon of org€inlc matter such as peat or submerged wood was encountered, except for an occasional woody fragment or kankar nodule.(Figs.33 and 3^)»

Pollen Analysis

Samples for pollen analysis were collected at intervals of 5 cm throughout the profiles, except at Aksa and Manori, where they were spaced at intervals of 10 and

2.5 cm respectively.

The procedure for maceration was as follows :

Samples were first treated with 10^ KOH, then HF, subsequently acetolysed and finally mounted in glycerine

(Faegri and Iversen, I95O ). The coarse debris left on the

sieve after the initial alkali treatment was examined under a low-power binocular microscope. No seeds or fruit were found. The debris consisted of a few indeterminate fragments or shreds of cuticles and a few microforaminifera. Organic material derived from plants was negligible.

To support the identification of sub-fossil pollen and spores, pollen slides of present>day species of mangrove plants were prepared, also by the acetolysis method. They were examined and their morphological details listed in the form of a workable key to assist identification.

The only available information on modern pollen in the area is an unpublished annual pollen calendar for Bombay

(Vishnu-Mittre and O.Anchein, I 968). This shows an overall 229 poverty of pollen on the slides. Neither mangrove species nor those of the deciduous forests are present in the aerial pollen content. This could be due to :

a) dominance of insect pollinated species;

h) low-pollen producing plants;

c) possibly unfavourable circulation of

wind currents for the dissemination of

pollen within the city.

For the relative pollen production of mangrove plants, Muller*s observations (1962) were taken as a standard,

Rhizophora. Ceriops. Brugulera. Sonneratia spp. and members of Chenopediaceae produce relatively high amounts of pollen, while AVicennia produces less. Among the other species.

Acanthus. Clerodendron and Sesuvium are insect pollinated.

In the Bombay marshes, as observed today, the large pollen producers are rare, and Avicennia is the most widely distributed species.

Results

The toteil number of pollen grains recovered from each sample (five slides per sample were counted), even after attempts to concentrate the pollen content, was less than iOO grains, and in most cases less than 50; insufficient for any statistical eveduation. In view of the pollen deficiency, only the following tentative comments have been offered.

An experimental pollen diagram was, however, prepared by bringing the number of pollen grains from each sample upto a total of iOO (Fig. 35 ). 230

The following comments are based on this.

Though the pollen of Rhlzophoraceae increase towards the top of the profile, the pollen of Rhizophora mucronata was not observed. Bruguiera and Ceriops appear to be the species represented. Rhizophora does not occur in this swamp today.

Avlcennia-1ype pollen is poorly represented inspite of the present-day dominance of Avicennia alba.

Bxcoecaria agallocha (Geva Surrun Phimgali).

Sonneratia acida and Acanthus ilicifolius are indicated by the sporadic occurrence of their pollen grains and among them, the pollen of Sonneratia is better represented.

Upland vegetation is represented by the pollen of

Malvaceae (Salmalia malabarica). Myrtaceae, Leguminoseae,

Euphorbiaceae (Phylanthus). Holoptelea. Meliaceae and

Urticaceae. Associated ground vegetation comprises

Compositeae, Crucifereae and Gramineae.

Large-sized grass pollen (82-100 ) was encountered at a depth of 140-145 cm in the profile; big enough to be that of Zea mays Linn., or another species of wild grass.

A few pollen grains of Abies/Picea were identified at a depth of 3.90-4.00 m. As it is unlikely that these coniferous species were aerially transported over this long distance, the writer feels that their presence could be the result of laboratory contamination. 231

Among the freshwater species a single grain of

Typha was found in a basal sample.

Discussion

The negligible amount of Avicennia pollen, inspite of its being the dominant species today in this area, might be due to its low pollen production and biotic influences.

Both the mangrove vegetation and upland forests have been intensely affected by the latter. Trees and plants have been cut down and vast areas cleared to provide fuel, fodder and land for recleimation. Cattle graze on the foliage of Avi cennia and Acanthus (Navalkar, 1956), so that the now stunted and bushy forms of these species rarely attain a height of more than 2 m. This may have led to the selective decline of certain species.

The pollen of Rhizophora was not identified in the samples, it occurs only sparsely today and this may also have been the case in the past. The relatively higher values for other Rhizophoreae and Sonneratia acida. suggests that they were more profusely present in the past. Excoecaria. Acanthus.

Atripiex and Suaeda spp. are present both in the samples as well as in the modern vegetation.

The paucity of pollen and spores in these sediments is partly due to the low pollen production of most of the mangrove species, but may also be due to the destruction of pollen in these sediments, a high rate of sedimentation and possibly the chemical nature of the swamp clays. 232

The soils of the modern marshes of Bombay are characterised by a high chloride content (0.78 to 3 .^ 7 ), almost as high as that of sea water (0.9 to 3.59)

(Bharucha and Navalkar, 19^2). Rainfall and temperature, however, produce fluctuations in this concentration. It is not yet known whether a high concentration of chloride in the soil is adverse to the preservation of pollen.

Alkalinity of the soil may be partly responsible for the destruction of pollen. The soils of the Bombay mangrove sweimps are more or less neutral with pH 6.81 in the winter months and 7*03 during the monsoon. The sea water, however, is distinctly alkaline with pH 8,0

(Navfilkar and Bharucha, i9^8). These swamps are flooded twice a day by the high tide and the shell fragments, calcareous nodules and foraminifera tests, all probably combine to increase soil edkalinity.

The mangrove sediments inspite of waterlogged conditions and poor aeration are poor in humus, its content varying between i~2%. Navalkar and Bharucha (1949) are of the opinion that decaying organic matter is probably washed out by the tides. I f this is so, then it could also be another factor to account for the lack of pollen. Samples sent for ±kC dating were rejected as unsuitable for this reason.

Mi croforami ni fera

In relation to the number of pollen grains present, a large number of microforaminifera were observed on the slides 233 inspite of HCl and HF treatment. They occur in greater numbers in the upper part of the profile, a slight decrease

is noticed at i .5 m emd below 3 m they are absent. Their

sizes range from 25 to 160 ju. Biserial emd close-coiled

forms dominate, followed by the Globigeriana-type and

loose-coiled forms. Uniperial types and Ostracoda are

poorly represented.^

It is unusual for foraminifera to escape

destruction during acetolysis treatment. However, similar

instances have been recorded elsewhere (Wilson and

Hoffmeister, 1952; Wetzel, 1957; Van Veen, 1957; Muller, 1959).

The present concensus of opinion indicates that these

specimens are the' chitinous inner linings of the tests of

marine formaminifera. Their relatively small size, however,

distinguishes them from the more common genera, hence the

term "raicroforamdnifera", referring to "these small but

sometimes fully grown representatives of a restricted group

of genera" (Muller, 1959x22).

Their presence in these marsh s£imples is certainly

indicative of brackish to marine conditions. Had they been

found in larger numbers and had the^e been adequate pollen

representation, it would have been Interesting to ascertain whether an increase or decrease in their number could be found

to coincide respectively with a rise or fall of the sea level in this area.

^Identification of microforaminifera was carried out by O r.S.K . Singh and Dr.P. Kalia, Geology Depeurtment, Lucknow University. 23k

Mlcroplankton

As many as seven types of microplankton were observed on the slides, of which Types I and V are dominant In the lower samples and Types II and II I are dominant In the upper levels. In the absence of any detailed studies they have been tentatively Identified as cf. Palaeohystrlchosphora and cf. Baltlsphaerldlum

(K .P. Jain, personal communication). 235

Appendix 2

Modern Beach and Dune Sands Iron Bombay :

Mecbanical Analysis

In order to discover whether or not tbe grain size distribution curves of modern beach and dune sands show significant variation, the writer collected samples from two localities in the Bombay area, Manori and Gorai (Fig.i3>*

The size cumolative curves are shown in F ig .36.

As can be seen, the beach samples from both sites are moderately sorted, and the dune sample from Gorai, well sorted, as would be expected. The dune sample from Manori, however, shows little variation from the beach sand from both localities. The relatively poor sorting of sand from the Manori dune could be partly ascribed to the short distance, over which beach sands were transported at this locality.

Samples collected from different parts of any beach are likely to show variations in the degree of sorting

(Kukal, i97i:209>*217). This is also demonstrated in the vctLues for beach sands from and Ratnagiri, Table 5

Nos.5 and 6, where several samples were collected from each locality, both near the high water level and low water level.

The mean size, sorting index, skewness and kurtosis values for the Manori and Gorai samples were worked out according to Folk and Ward in King (1966, Chp.6:273-279). 236

The results of the dune samples are shown in Table 5

(Nos.1,2) while the values for beach sanples are shown in Table 5 (No s . 3»^) together with the values for beach samples from Alibag (N o.5) (Muthuraraan, 196?) and

Ratnagiri (No.6) (Purandhare, 197i)«

Compared with the scule suggested by Folk and tfard (in King, 1966), the mean size values of beach sand, both from Gorai and Manori, are slightly less than the ideal (2,82) values. The sample from the Manori dune is also slightly less than the ideal, while that from the

Gorai dune matches completely (2 .8 6 ). Statistical tests, however, show that the sizes tend to be so close, as to be of little value in differentiating the environment of sedimentation.

The graphic standard deviation values of the

Bombay samples when compared with those of Folk and Ward are, both in the case of beach and dune sediments, greater than the values suggested.

The negative skewness values of the beach samples appear to match the standard, but those of the dune samples do not. The kurtosis values also are all higher than those suggested by Folk and Ward. On the other hand, the samples from Bombay, when compared with those from Alibag and

Ratnagiri, are well matched.

Sphericity and roundness studies were not carried out on these modern beach and dune sediments. A comparison 237 of these parameters, as well as mechanical analysis, was, however, earlier worked out for karal samples and dune samples from Manor! and Marve by Avasia (in, Agrawal et al.,1973)>

Table 5

Site Mean Size Sorting Index Skewness Kurt0sis

i . Manori (D) 2.76 0.55 -0.42 1.92

2 . Gorai (D) 2.86 0.4i -0.06 1.23

3* Manori (B) 2.71 0.93 -0.24 1.12

Gorai (B) 2.56 0.68 -0.17 1.15

5. Alibag (B) 3.07-3.70 0.39-0.64 -0.10-0.29 0.97-1.59

S, Ratnagiri (B) 2.07-3.14 0.33-0.89 -0.04-0.52 0.93-2.34 238

Appendix 3

Note on Llthology and Palaeontology of a Karal Sample from Brangal Bhattl, Bombay

A sample of karal from an excavated pit at

Brangal-Bhattl, about 3 m below the surface was sent to the National Institute of Oceanography, Panaji, Goa for ancdysis. Below is the report sent by Dr.M.G.A.P. Setty,

Scientist-in-Charge, Geological Oceanography Section,

Lithology

It is a sugary surfaced, hardened, compact sandstone. It is highly porous and the indiridual seuid grains and the contained fauna is loosely held together by a cementing material of CaCO^. It can be broken down with a little pressure. The term * sandstone* is used in the larger sense of the word only.

Contained Fauna

Foraminifera and other associated fauna was separated in the usual manner and when examined under the microscope the sample revealed :

(a) Ammonia beccari (predominant)

and variants ...... i5 20%

(b) Blphidium excavatum ...... 2-55J

(c) Quinqueloculina seminulum

and Milliammina fusca ...... 239

(d) Ciblcldes mollis and

Nonlon formosam ...... rare, only traces

In addition there appear fragments of shells, wood ajid whole and fragmented Osvraccds and also hits of coral.

This faunal assemblage constitutes nearly 25 ** 30^ in the given sample.

A m m o n ia heccari and variants, Blphidium excavatum.

Quniqueloculina semminulum and Milllfunmina fasca are very characteristic of the beach or turbulent zone of the littoral zone. They are also found in estuarine shallow water regions.

The presence of wood fragments, highly fragmented shells and foraminifera like Ammonia, Quinqueloculina and

MilliamBtina indicate a very shallow and highly turbulent zone.

Ammonia beccari is found very abundantly and is characteristic of 5 “ 60 fathoms (maximum) having a temperature range of i8 - 25^C, but capable of withstanding upto 3i° C. Hence it is very commonly found in almost all the beach sands of the tropical, sub-tropical and transitional areas of the world. It is common in saline waters but it is tolerant of brackish conditions also. Its association with similar minor forms as stated above further supports this view.

Since it is the predominant species in the faunal assemblage it may be deduced that the environmental conditions 240 of deposition of this material presupposes beach and/or estuarine conditions.

It is very characteristic that no planktonic foramlnifera is seen in the material. 241

Appendix k

Note on the Petrography of some Karal Samples from the Konkan

by

N. S. Ghate • University of Poona

S. N. Rajaguru -> Deccan College

In all six samples of karal from the Konkan were studied under a petrological microscope. Owing to the friable nature of some of these rocks their impregnation

In Canada balsam prior to thin sectioning was not as perfect as that obtained with more modern techniques of impregnating such friable material by epoxy resins under vacuum conditions

(Brewer, 1964). Consequently this factor has set certain limitations on our petrographlc interpretations. The following discussion cind inferences regarding the petrography of kareJ. should, therefore, be treated as only tentative.

Sample No.i : Hirya Bhatti, Ratnagirl

Open clastic texture with poor grain to grain contact, skeleton grains of shell fragments, peloids, rock nodules, and quartz are embedded in a crystalline to microcrystalline calcite.

Sample No.2 : Mutha Bay, RatnagirL

Skeleton grains of shell fragments, rock nodules, silt nodules, peloids, iron concretions, quartz, felspar and a few foramlnifera are found in a calcareous clayey matrix. Secondary recrystallisation of original shell is 2 k 2 quite clear in this section.

Sample No.3 : Spit, Ratnagizl

The section shows more or less the same petrographic characters as No,2. Skeleton grains of quartz are angular to subangular and calcareous cutans

(coatings) around these grains is also d e a r .

Sample No.4 i Ereingal-Bhatti, Bombay

Owing to the thickness of the section the skeletal grains, particularly quartz, do not show good petrographic characters. Only one semi-altered plagioclase grain was detected. The skeleton grains of shell fragments and other mineral matter are embedded in a crystalline to microcrystalline mass of calcite.

Sample No.5 t Manori, Bombay

Bock nodules present are highly altered. Glass fragments are abundant. Other skeleton grains are similar in composition to those in No.4 , and show open clastic texture with a dominance of crystalline and microcrysteilline calcite in the siatrix. The secondary recrystallisation of shell fragments is common.

Sample No.6 : , Thana

The sample shows coarse, compact clastic texture with a marked development of crystalline calcitic matrix and cement around the subrounded grains of rock nodules. 243

silt nodales, pelolds, shell fragments and foramlnifera.

Recrystalllsatlon of primary shell carbonate Is very marked.

These preliminary petrographic studies of karal

from the Konkan only show that the primary carbonates,

such as shells, are fragmentary and are partially recrystallised to calcite and are embedded In a purely secondary crystalline to microcrystalline calcitic mass.

It is , therefore, concluded that these rocks are not very 14 suitable for C dating. Radiocarbon ages obtained for

these rocks are 'minimum ages* (Polach, 1969) and a finite

£Lge of these samples is not possible. We strongly recommend detailed X-ray diffraction einalyses of these specimens in order to determine the exact nature of recrystallisation.

On the basis of the distinction into various types of lithified formations discussed in Part I I I , A .5, the writer adds that from the above samples. Nos. 2, 3 and

6 are intertideJ. beachrock, while Nos.i, 4 and 5 are beach- dune complex rocks.