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of Europe ; and the external aspect of the blocks was almost trachytic in
its roughness. Not far hence, the gneiss with which the diallage is asso-
ciated, apparently as a large vein, loses its mica, which is replaced by minute
silver scales of graphite.

Gneiss is the prevalent rock about Bangalore, penetrated by dykes of
basaltic greenstone, and occasionally by granite, as is seen near the petta
and adjacent fields. The granite in these localities splits into the usual
cuboidal blocks or exfoliates into globular masses. It often contains horn-
blende in addition to mica. The gneiss strata, though waving and contorted,
have a general north and south direction, and often contain beds of whitish
quartz preserving a similar direction. The strata are nearly vertical.
Approaching Bangalore from the north-west, a bed of laterite is crossed,
forming a hill (Oyali dinne) on which stands a small pagoda. This bed
extends northerly in the direction of Nandidroog, where laterite also occurs.
In other situations, covering the gneiss and granite, a reddish loam is usually
found, varying from a few inches to twenty feet in depth, containing beds of
red clay, used in making tiles, bricks, tS:c. ; the result evidently of the
weathering of the granite, gneiss, and hornblende rocks. A similar formation
continues to Kolar. The gneiss is occasionally interstratified with beds of
hornblende schist. Granite, gneiss, and hornblende are the prevailing rocks
at Betmangala. About eight or nine miles east of this the Mysore frontier is
crossed into South Arcot. Kunker occurs on the banks of the rivulet near
the village, both on the surface and in a bed below the alluvial soil.
Efflorescences of muriate of soda are also seen in the vicinity.

From Sermo;apatam to Coorg, by the same.

From Seringapatam my route lay westward over a stony, kunkerous,
uneven, and rather sterile tract to the banks of the Lakshmantirtha. The
formation at Hunsur is a micaceous gneiss with veins of quartz, and beds of
the same mineral evidently interstratified with the layers of gneiss. These
beds, on weathering, leave the surface-soil covered with their angular and



TRAVERSE NOTES 35

rust-stained fragments. Glimmering hornblende rock, veined with milky
quartz, and a pale tlesh-coloured felspar alternate with the gneiss. The
outgoings of two or three dykes of basaltic greenstone are passed on the
roadside. The surface of the country from Seringapatam gradually rises as
it approaches the Ghats.

The country between Hunsur and the Ghats is a succession of rocky
risings and falls of the surface, covered for the most part with reddish alluvial
soil, over the face of which are scattered numberless angular fragments of
the surrounding rocks ; especially white and iron-stained quartz, and occa-
sionally kunker. Some of these alluvia have not travelled far, since we often
find the colour of the surface-soil a true index to the nature of the rock
beneath ; viz., dark red or coffee-coloured soil over hornblende rock and
trap ; light red to sandy soil over gneiss and granite ; light greenish-grey
over talc schist ; and white, or what is nearly white, over felspar and quartz
rocks. The quartz beds, being usually harder than their neighbours, are
written in white bas-relief characters over the face of the country. They
never weather — like the felspars, hornblendes and micaceous rocks — into
clay, but usually break up into fragments by imperceptible fissures, into
which water, impregnated with iron from the surrounding weathered rocks,
soon insinuates itself and stains the rock. At length the particles composing
the fragments themselves lose their cohesion and break up into an angular
gritty sand.

At Periyapatna basaltic greenstone is seen in the bed of a nullah crossing
the gneiss and hornblende rock, and veined with kunker. Large blocks of
fine red granite are seen in the ruined fort walls, brought evidently from no
great distance. The Ghat line west of Periyapatna presents a succession of
round-backed hills and smooth knobs, which continue to Virarajendrapet in
Coorg. Their surface is covered with dark vegetable mould, and shaded by
a fine forest, the roots of which strike into the red loam or clay on which
the vegetable mould rests. It produces excellent sandalwood.



At tJic Grrsoppa Falls, by the same.

The precipice over which the water falls affords a fine section cf gneiss
and its associated hypogenc schists, which dip easterly and northerly away
from the Falls at an angle of about 35°. The gneiss is composed of quartz
and felspar, with both mica and hornblende, and alternates with micaceous,
talcose, actinolitic, chloritic and hornblende schists, imbedding (especially
the latter) iron pyrites. These rocks are penetrated by veins of quartz and
felspar, and also of a fine-grained granite, composed of small grains of white
felspar, quartz and mica. The mass of hypogene rocks has evidently been
worn back several hundred feet by the erosion and abrasion of the cataract ;
the softer talcose and micaceous schists have suffered most. Rock basins
are frequent in the bed of the river, which is worn in the rock and rugged
with water-worn rocky masses.



36 GEOLOGY

From J alar pci to Shikarpur {in iSSi),' by R. Bruce Footc, F.C.S.

The results of comlsincd traverses show that the Mysore table-land is
traversed by great bands of granitoid and schistose gneiss, the southerly
extensions of some of the great bands recognized in the South Mahratta
country. When the whole of this region shall have been geologically
examined it is more than probable thnt all the bands known to the north of
the Tungabhadra will be traced far to the south. The traverse now to be
described shows that three great bands of schistose rock occur on the
Mysore plateau, and that two of these are actual continuations of two of the
great schistose bands in Dharwar District. For convenience of description
these bands will in the sequel be referred to as the " Dharwar-Shimoga "
and " Dambal-Chiknayakanhalli" bands. Both these bands have been
traced across the Tungabhadra, the latter in a chain of hills running down
southward to Chitaldroog and Chiknayakanhalli, while the former forms
another chain of hills passing Harihar and Shimoga and stretching further
south towards Hassan. These bands are of considerable width, the Dambal-
Chiknayakanhaili band, which is considerably the narrower of the two,
measuring i8 miles across where crossed by the line of section. In addition
to their geological interest, these two bands are of importance, as within
their limits occur several of the auriferous tracts which have of late attracted
so much attention. The Dharwar-Shimoga band is slightly auriferous at
its northern extremity, and streams rising on it near Bail Hongal and
Belavadi in the Sampgaon taluq of Belgaum District used formerly to be
washed for gold. The auriferous tract of Honnali lies within the same
schistose band a little to the north of Shimoga. The Dambal-Chiknaya-
kanhalli band contains the auriferous tract of the Kapputgode hills near
Dambal, to the north of the Tungabhadra ; while south of that river, on the
Mysore plateau, near the town of Chiknayakanhalli, are quartz reefs reported
to be auriferous, and which have attracted the notice of several speculators,
who have taken up land for mining purposes.

This schistose band is seen to stretch away far to the south-south-east in
a line of low hills, and is said to extend to Seringapatam, passing that place
and the town of Mysore to the eastward, and then trending round to the
south-west and continuing into south-eastern Wyndd, where it forms the
gold-field around Devala. This tallies with Mr. King's observations in the
Wyndd, a strong band of schistose gneiss having been shown by him to
occur at and around Devala, in which chloritic schists occupy an important
position. My informant as to this extension of the Dambal-Chiknayakan-
halli band was Mr. Lavelle, the pioneer gold-prospector of the present time,
who has traced the band from the Wyndd north to beyond Chitaldroog. I
have no doubt but that Mr. Lavelle's observations will be fully confirmed
when the whole of Mysore shall have been surveyed geologically. If the
parallelism of strike continues between the southward extension of the

Dharwar-Shimoga band and that of the Dambal-Chiknayakanhalli band,

' Records of the Geological Survey of India, Vol. XV., Part 4.



To face page 36.



Kolar Goldfield Jalarpet

Junction




JS '^ 3-9

\ranitoid gneiss.



SHIKARPUR



Jotn-Bai-tliolonirw A Co .X din'



SKETCH SECTION FROM JALARPET TO KALVARANGAN BETTA NEAR SHIKARPUR

After R. Bruce Foote, F.G.S.



TRAVERSE NOTES 37

it is highly probable that tlie former will be found to constitute the auriferous
tract said to exist in the north Wyndd. The stratigraphical relations of
the several great bands, both granitoid and schistose, have yet to be worked
out, for in the northern part of the great gneissic area they were found too
obscure to be satisfactorily explained, and it remains to be seen whether
they represent two or more great systems. Their position and relation are
shown in the accompanying map and section.

If the line of section be followed from south-east to north-west it will be
seen to traverse a region of very typical granite-gneiss, extending from
Jalarpet Junction (Madras Railway), for a distance of some 30 miles. This
granite-gneiss tract forms the eastern edge of the great Mysore plateau,
which is here a wild, rugged, picturesque jungle region.

To the west the section crosses at its narrowest part the band of schistose
rocks in which lies, a little to the north of the railway, the now well-known
Kolar gold-field, at present a scene of energetic mining work on the lands
taken up by a number of large Mining Companies. This schistose band,
which will be most appropriately called the Kolar schistose band, forms an
important synclinal trough resting on the adjacent granite-gneiss rocks. It
is the only one of the great schistose bands whose relations to the associated
bands of granitoid rocks have (as yet) been distinctly traced. A fuller
account of this band with especial reference to its auriferous character will
be given further on. {Sec p. 43.)

On crossing this Kolar gold-field band, the section trends northerly as far
as the Bowringpet railway station, when it bends sharp round to the west
and continues in that direction as far as Bangalore. The very broad band
of granitoid gneiss, which extends between the Kolar gold-field schistose
band to the second great schistose band (the Dambal-Chiknayakanhalli
band), forms in its eastern part an open undulating plain from which rise a
few important rocky hills, as the Tyakal, Balery and Vakkaleri hills north of
the railway. A number of small low table-topped hills are also to be seen
at small distances from the railway, as the Betarayan Betta, 3J- miles north-
east of Bowringpet railway station, the Patandur hill, 2 miles south-west by
south of the Whitefield railway station, and the low hillock crowned by a
mantapam about a mile north of the Maharajah's new palace at Bangalore.
These three hillocks are capped with beds of true sedimentary lateritc under-
laid by lithomargic clays. Of precisely the same aspect, both in form and
colour, are the Sivasamudra, Jinnagra and Chikka Tagali hills, which lie a few
miles north of the railway near the Whitefield and Malur stations. Identical
in form and appearance also is a much more extensive development of
table-topped plateaus, which are well seen from Betarayan hill, lying several
miles to the north and covering a considerable area. The lateritc at the
north-eastern end of the Patandur hill is distinctly conglomeratic and con-
tains a tolerable number of well- rolled quartz pebbles. The red colour of
the sides of these hills and plateaus, added to their sharp-cut tabular shape,
makes them conspicuous from considerable distances. No organic remains
were found in connection with these lateritc beds, and the number of sections
examined was not sufiicient to enable me to form any positive opinion as to



38 GEOLOGY

tlicir origin, and sUll less so as to their geological age, — but there can be no
doubt that they are the scattered outlying remains of a formerly far more
extensive formation.

To the north-west of Bangalore the undulation of the country increases
considerably, and the streams run in much deeper channels, affording more
numerous sections both of the surface soil and sub-rock. The surface of
the country is generally covered with a thick layer of red soil, which often
contains a large percentage of pisolitic iron (haematite) in segregational
form.

Thirty-two miles north-west of Bangalore the section cuts across the line
of hills' running north and south from the Kdvdri river, a little east of the
great Falls, up to Nidugal on the frontier of the Anantapur District. This
line of hills culminates close to the section in the fine peak of Sivaganga,
which attains the height of 4,559 feet above sea-level. Like many other
groups of granitoid-gneiss hills in the south, these hills are very rocky and
bare, and look as if they had never been covered with a real forest growth.

The section maintains its north-westerly course up to Tumkur, beyond
which town it turns suddenly westward and, after a course of 16 miles,
in which remarkably few outcrops of rock are seen, meets the second great
band of schistose rocks in the line of hills rising between Hagalvadi and
Chiknayakanhalli. This second great band of schists is the southerly
continuation of the Dambal-Chiknayakanhalli schist band as defined above.
The width of this extremely well-marked schistose band, which the section
crosses at right angles, is 18 miles. The character of the scenery is
markedly different ; smooth, grass-grown hills, generally well rounded, with
very few conspicuous exposures of rock, take the place of the bold rocky
bare hill masses seen east of Tumkur. The rocks consist of hornblendic,
chloritic and hjematitic schists cropping out at very high angles or in
vertical beds. Several large quartz reefs occur traversing these schists, and
one large one crosses the road some distance west of Doddiganhalli. Time
did not allow of my doing any prospecting here, but several prospectors
have stated that their researches were rewarded by the discovery of gold in
appreciable quantity both in the quartz and by washing the local soils. The
extension southward of this schist band may be traced by the eye for many
miles, owing to the very characteristic features of the low line of heights
which extends south in the direction of Seringapatam. That they extend
still further south and then trend south-westward into the south-eastern part
of the WynAd may be assumed as a fact on the strength of the information
kindly furnished by Air. Lavelle. The contact of the schists and granitoid
gneiss is unfortunately concealed by superficial deposits at the places where
the section cuts across their respective boundaries ; but the impression left
in my mind by the general appearance of the localities was that the schists
were overlying the granitoid beds, and the same relation appeared to me to
exist in the Dambal gold-field, as far as its v.^estern boundary is concerned.

' The expression line of hills is used in preference to the term chain, as there is
little continuity of high ground, the hills being mostly quite detached and separated
in some parts by considerable spaces.



TRAVERSE NOTES



39



The eastern boundary of the schist band was not traced near Dambal and
Gadag, but further north it is completely hidden by the tremendous spread
of cotton soil there prevailing. Passing on a little to the south of west from
the schistose band the section runs across a granitoid-gneiss region, and
after passing Tiptur crosses the watershed between the Kdveri and Krishna
hydrological basins, the section trending more and more north-westerly
along a rapid descent. It leaves the high, picturesque, granitoid hill masses
of Hirekal Gudda and Gardangiri to the right, and beyond Banavar skirts
the eastern boundary of the third or Dharwar-Shimoga schist band for
several miles, but does not actually leave the granitoid rocks till it has
passed Kadur by some six miles. The rocks of this granitoid band, which
may for convenience be called the Mulgund- Kadur band, offer no
speciality calling for remark. Like the hilly region running east of Tum-
kur, the hills may preferably be described as forming a line rather than a
chain, for they occur in numerous detached masses.

As just mentioned, the section gets on to the third schistose band six
miles to the north-west of Kadur, and here the schists are mostly chloritic
of pale colour with intercalated more highly siliceous bands, ranging from
chloritic gneiss to quartzite. To the south of the road the quartzites
increase much in development and rise into a high ridge with a great cliffy
scarp on the eastern face of Coancancul peak. Further west, to the south
of the high road, rises a considerable hill of very rugged nature, which,
when seen from a distance, presents great resemblance to a typical granitoid-
gneiss hill. On closer approach the rock is seen to have a very coarsely
mottled structure, which turns out to be due to the presence of enormous
numbers of well-rounded pebbles of a granite or compact granite gneiss.
The size of the included stones ranges in the part I examined from small
pebbles to small boulders, all enclosed in a greenish-grey foliated chloritic
matrix. The thickness of the conglomerate here exposed must be very
great, as proved by the size of the hill which goes by the name of the Kal
Droog. To the north, the beds are soon lost sight of under the local
alluvium of the Kushi river, and they are not seen to reappear conspicuously
in the hilly country on the north side of the valley. To the west of the great
conglomerate beds follow more schistose beds, and, as seen on the hill slopes
south of the road, a great series of quartzites. Near Tarikere, and to the
north-west of it, very few exposures of rock are met with as far as Benkipur,
but the few that do show through the thick woods which here cover every-
thing, prove the country to be formed of schistose members of the Gneissic
Series. About four miles north-west of Tarikere the road crosses a very small
outcrop of typical hiumatite schist, striking in a northerly direction. A good
deal of rock shows in the bed of the Bhadra river at and above Benkipur,
but the forms seen are not very characteristic, and at the time of my passing
everything was obscured by a thick layer of slimy mud left by a high fresh
in the river. This part of the section would be very unsatisfactory were it
not that the schistose character of the beds forming the line of hills extend-
ing northward parallel with the valley of the Bhadra shows quite clearly the
extension of the rocks seen south-east and east of Tarikere. Between Ben-



40 GEOLOGY

kipur and Shimoga very little rock of any sort is seen, but about half-way
across the Doab, between the Tunga and Bhadra rivers, a band of fine-
grained grey granite gneiss is crossed, while to the east and south of
Shimoga town are several conspicuous large masses of a chloritic variety of
granite gneiss. The exact relation of these granitoid outcrops to the great
schist series further east I had not the opportunity of determining, and am
not quite certain whether they represent the eastern border of another great
granitoid band, or whether they are part only of an unimportant local band
of granitoid rock. I am inclined to think the latter will be found the real
condition of things when the country comes to be fully surveyed. The short
space of time at my command prevented my making a detour to settle this
point. Here, too, the extent and thickness of the jungle growth greatly hide
the general surface of the country along the road, while the rainy or misty
character of the weather tended much to obscure the appearance of hills at
but very moderate distances. Though the exigencies of dak travelling com-
pelled me to make the detour to Shimoga instead of following the line of
schistose beds northward from Benkipur, I am perfectly satisfied as to the
fact of these schists continuing northward, and joining those which cross the
united rivers forming the Tungabhadra, a few miles below the junction of
the Tunga and Bhadra. The country here is much freer from jungle, and
many ridges of rock, consisting of quartzites and chlorite schists with rocks
of intermediate character, can be traced for miles. This part of the section
extends from the bank of the river for rather more than 20 miles, — from
the travellers' bungalow at Holalur north-westward to the Ta\ankal-betta
Trigonometrical Station, six miles east-by-south of Shikarpur. Along the
12 miles of road between Shimoga and Holalur but little is seen of the
older rocks, the road lying close to the left bank of the Tunga and Tunga-
bhadra, and passing almost entirely over the river alluvium which at and to
the north-east of the Holalur bungalow forms a coarse bed of rounded
shingles, rising a considerable height above the present high flood level of
the united rivers.

The most striking features, both orographically and geologically, of this part
of the Mysore country are the quartzite outcrops, which are numerous, but
of which only the principal ones require notice. Of these the best marked,
longest and highest culminates in the Kalva-Ranganbetta, a fine hill rising
some 1,200 feet above the plain, and 3,388 feet above sea-level, 16 miles
to the north of Shimoga. The out-crop of the great quartzite beds forming
this ridge has a distinct dip of some 6o°-65° (on the average) to the north-
east. The quartzites are underlaid by a schistose (chloritic) series, the south-
western extension of which was not ascertained. Overlying the quartzites,
which are generally flaggy in character (but which here and there become so
highly charged with scales of pale green chlorite as almost to lose their
quartzitic character, and pass into chloritic gneiss), are local beds of true
conglomerate, — the first I have met with or heard of in the gneissic rock of
the peninsula. The conglomerate has evidently imdergone considerable
metamorphosis, but its real character and truly clastic origin cannot be
doubted when carefully examined. Many of the included pebbles appear to



HONNALI GOLD-FIELD 41

have been fractured by the great pressure undergone, but their truly rounded
character is quite distinct and unmistakable. The beds seen by me and
traced for several hundred yards, are exposed a little way up the slope of
Kalva-Ranganbctta peak, and a little to the north-west of a small, but rather
conspicuous, pagoda, which stands in a little recess. The included pebbles
in the conglomerate consist chiefly of quartz, a few of gneiss, and some of
what appeared an older quartzite. A second intended visit and closer
examination of this very interesting bed was prevented, much to my sorrow,
by bad weather. The second in importance of the quartzite ridges has its
eastern extremity in the bed and left bank of the first west-to-east reach of
the Tungabhadra below the Kudali Sangam, or junction. West of the new
high road from Shimoga to Honnali the quartzite beds rise into the Phillur
Gudda (hill), and beyond that rise again into a considerable hill some 400
to 500 feet high, and may be followed easily for several miles to the north-west.
The quartzitic character is then in great measure or entirely lost by the rock
becoming highly chloritic, and the beds can no longer be safely distinguished
from the surrounding mass of chloritic schist. In the north-westerly part
of this Phillur Gudda ridge several pebbly beds were observed intercalated
between the more or less chloritic quartzite. Tiicy differed from the Kalva-
Ranganbetta beds in being less coarse and having a more chloritic matiix,
but had undergone about an equal amount of metamorphosis. A consider-
able number of quartzite ridges are intercalated between Phillur Gudda
ridge, and the southern end of the Kalva-Ranganbetta ridge, which
terminates in the Nelli Gudda Trigonometrical Station hill, seven miles west-
north-west of the Kudali Sangam. To these ridges may be ascribed the
existence of the group of hills they occur in, as but for their greater durability
and resisting power to weather action, they would certainly have been worn
down to the low level of the purely chloritic part of the schistose band, both
to the north-west and south-east. Unless there has been an inversion of



Online LibraryB. Lewis (Benjamin Lewis) RiceMysore: a gazetteer compiled for government (Volume 1) → online text (page 6 of 98)