d the
successive peat-beds seem to imply that the subsidence of the ground was
gradual or interrupted by several pauses. Below the vegetable mass they
entered upon a stratum of yellowish clay about ten feet thick,
containing horizontal layers of kunkar (or kankar), a nodular,
concretionary, argillaceous limestone, met with abundantly at greater or
less depths in all parts of the valley of the Ganges, over many
thousand square miles, and always presenting the same characters, even
at a distance of one thousand miles north of Calcutta. Some of this
kunkar is said to be of very recent origin in deposits formed by river
inundations near Saharanpoor. After penetrating 120 feet, they found
loam containing water-worn fragments of mica-slate and other kinds of
rock, which the current of the Ganges can no longer transport to this
region. In the various beds pierced through below, consisting of clay,
marl, and friable sandstone, with kunkar here and there intermixed, no
organic remains of decidedly marine origin were met with. Too positive a
conclusion ought not, it is true, to be drawn from such a fact, when we
consider the narrow bore of the auger and its effect in crushing shells
and bones. Nevertheless, it is worthy of remark, that the only fossils
obtained in a recognizable state were of a fluviatile or terrestrial
character. Thus, at the depth of 350 feet, the bony shell of a tortoise,
or trionyx, a freshwater genus, was found in sand, resembling the living
species of Bengal. From the same stratum, also, they drew up the lower
half of the humerus of a ruminant, at first referred to a hyaena. It was
the size and shape, says Dr. Falconer, of the shoulder-bone of the
_Cervus porcinus_, or common hog-deer, of India. At the depth of 380
feet, clay with fragments of lacustrine shells was incumbent on what
appears clearly to have been another "dirt-bed," or stratum of decayed
wood, implying a period of repose of some duration, and a forest-covered
land, which must have subsided 300 feet, to admit of the subsequent
superposition of the overlying deposits. It has been conjectured that,
at the time when this area supported trees, the land extended much
farther out into the Bay of Bengal than now, and that in later times the
Ganges, while enlarging its delta, has been only recovering lost ground
from the sea.

At the depth of about 400 feet below the surface, an abrupt change was
observed in the character of the strata, which were com