20 
Records of the Geological Survey of India. 
[vol. III. 
high level far above that attained by the rest of the bed in the neighbourhood can only be 
accounted for by one of three suppositions, either that it is a capping of clay carried up en 
masse by the hill whilst being protruded up through the alluvial group surrounding it, a 
supposition too unsupported by evidence to merit farther examination; or that it represents 
a remnant of a once continuous bed of like character, which once continuously stretched 
across and occupied to a coi’responding height, the country now forming the broad and low 
lying valley of the Ganges, to which also the like objection applies as to the last; or lastly it 
may have been originally deposited where we now see it on the hill side cotemporaneously 
with the rest of the bed, occupying the plains, when Patarghatta hill constituted a rock, 
submerged beneath the waters of that sea, which I have previously alluded to as at no dis¬ 
tant period occupying the plains of Bengal and upper India. 
Much stress should not perhaps be laid on the negative evidence of an entire absence of 
fossils in this clay, hut had it been formed by annual increments during Gangetic floods, it 
is not easy to understand how in such a homogeneous clay, and one so well adapted to pre¬ 
serve any mulluscous remains deposited in it, no shells are found, either such as occur so 
abundantly in river rejectamenta; or Uniones, for which it must have formed in places 
a congenial habitat. 
In the Ncrbudda valley a very similar clay occurs though at a higher level above the sea, 
and though shcdls are not common in it, yet such shells do occur in places, as are usually 
swept down into inundated tracts by river floods at present, as Bulimus pullus, Gray, Helhv 
Jallaciosa, Per. &e., as well as fine specimens of Uniones with valves united as in life, of 
species still living in the district ( U. Indians, Sow., and a fine variety of U. cwruleus, Lea.) 
The above are my grounds for inclining to the belief in the origin of the older allu¬ 
vial clay, in lower Bengal at least, and I will close my remarks on it by briefly describing its 
character and appearance. Where heat seen, in some steep .section on the bank of the Ganges, 
it presents the appearance of a stiff homogeneous clay, of a mottled yellowish or pale huffish 
hue reddening much by exposure to the atmosphere. It contains a small amount of fine sand, 
the presence of which in the fields and watercourses of the newer group is an unfailing 
indication of an approach to the boundary of the older. Dispersed through it also are 
numerous small ferruginous concretions like shots, but no foreign body either in the shape of 
pebbles or organic remains*, have to my knowledge been found in it. In some parts, as in 
the colliery districts about Rauigunj, where older groups of rocks cut out the alluvial deposits, 
gravelly beds surcharged with pisolitic oxide of iron, varying from a ferruginous gravel 
(in its consolidated shape termed laterite) to a bed sufficiently pure and unmixed to 
constitute a workable ore, occur stmtigraphieally subordinate to this alluvial clay, but they 
are mere local developments, varying in character, and influenced most probably by the 
nature of the rocks constituting the neighbouring country. With the exception of these 
gravelly, ferruginous and lateritic beds, which locally constitute a sort of bottom or 
junction lied of this day, we have no knowledge of what it rests ou save the rather meagre 
information to be gathered from the Fort William bore, neither do we know with certainty 
its total thicknessf or if any beds superior to it in position have ever covered it, except, 
should my view of their relations be the correct one, the sandy beds which in Purneah and 
the adjoining Zillahs seem to overlie, or perhaps in part replace it; which ignorance arises 
from the very uniform elevation over its entire area of so thick and homogeneous a bed, and 
the general absence of artificial sections deep enough to pierce this. 
Disseminated throughout this clay occurs the well known kunlcer or “ gooting”, occa¬ 
sionally in well defined nodules but more commonly in irregular stringy courses, and often so 
intimately commingled with the argillaceous portion of the bed, that the clay is dug in bulk- 
tor the kilns. Where this bed forms the surface of the country the more argillaceous portions 
are washed out, leaving the hunker strings, sheets and nodules projecting, or forming on the 
surface a sparse crust of “ gooting” pebbles, and this is more observable in the upper portion 
of the valley than iu lower Bengal, where the clay seems less rich in lime than to the 
north-westward. £ 
* Bovine bones were found in a well near Patna, at 60 feet. T. Oldham. 
t Its thickness cannot be regarded as under 60 feet. 
t Sir Charles Lyell, spe. king of the unchanged character of this clay (Principles. Vol. I, 429.) 1,000 miles north 
of Calcutta, doubtless inteLds the north-west, &c., above Calcutta following the course of the river. 
