In a geographical point of view the range of hills between Burdwan and the Soave is interesting, as being the north-east continuation of a chain which crosses the broadest part of the peninsula of India, from the Gulf of Cambay to the junction of the Ganges and Hoogly at Rajmahal. This range runs south of the Soane and Kymore, which it meets I believe at Omerkuntuk;* [A lofty mountain said to be 7000-8000 feet high.] the granite of this and the sandstone of the other, being there both overlaid with trap. Further west again, the ranges separate, the southern still betraying a nucleus of granite, forming the Satpur range, which divides the valley of the Taptee from that of the Nerbudda. The Paras-nath range is, though the most difficult of definition, the longer of the two parallel ranges; the Vindhya continued as the Kymore, terminating abruptly at the Fort of Chunar on the Ganges. The general and geological features of the two, especially along their eastern course, are very different. This consists of metamorphic gneiss, in various highly inclined beds, through which granite hills protrude, the loftiest of which is Paras-nath. The north-east Vindhya (called Kymore), on the other hand, consists of nearly horizontal beds of sandstone, overlying inclined beds of non-fossiliferous limestone. Between the latter and the Paras-nath gneiss, come (in order of superposition) shivered and undulating strata of metamorphic quartz, hornstone, hornstone- porphyry, jaspers, etc. These are thrown up, by greenstone I believe, along the north and north-west boundary of the gneiss range, and are to be recognised as forming the rocks of Colgong, of Sultangunj, and of Monghyr, on the Ganges, as also various detached hills near Gyah, and along the upper course of the Soane. From these are derived the beautiful agates and cornelians, so famous under the name of Soane pebbles, and they are equally common on the Curruckpore range, as on the south bank of the Soane, so much so in the former position as to have been used in the decoration of the walls of the now ruined palaces near Bhagulpore.
In the route I had taken, I had crossed the eastern extremity alone of the range, commencing with a very gradual ascent, over the alluvial plains of the west bank of the Hoogly, then over laterite, succeeded by sandstone of the Indian coal era, which is succeeded by the granite table-land, properly so called. A little beyond the coal fields, the table-land reaches an average height of 1130 feet, which is continued for upwards of 100 miles, to the Dunwah pass. Here the descent is sudden to plains, which, continuous with those of the Ganges, run up the Soane till beyond Rotasghur. Except for the occasional ridges of metamorphic rocks mentioned above, and some hills of intruded greenstone, the lower plain is stoneless, its subjacent rocks being covered with a thicker stratum of the same alluvium which is thinly spread over the higher table-land above. This range is of great interest from its being the source of many important rivers,* [The chief rivers from this, the great watershed of western Bengal, flow north-west and south-east; a few comparatively insignificant streams running north to the Ganges. Amongst the former are the Rheru, the Kunner, and the Coyle, which contribute to the Soane; amongst the latter, the Dammooda, Adji, and Barakah, flow into the Hoogly, and the Subunrika, Braminee, and Mahanuddee into the Bay of Bengal.] and of all those which water the country between the Soane, Hoogly, and Ganges, as well as from its deflecting the course of the latter river, which washes its base at Rajmahal, and forcing it to take a sinuous course to the sea. In its climate and botany it differs equally from the Gangetic plains to the north, and from the hot, damp, and exuberant forests of Orissa to the south. Nor are its geological features less different, or its concomitant and in part resultant characters of agriculture and native population. Still further west, the great rivers of the peninsula have their origin, the Nerbudda and Taptee flowing west to the gulf of Cambay, the Cane to the Jumna, the Soane to the Ganges, and the northern feeders of the Godavery to the Bay of Bengal.
On the 12th of February, we left Sheergotty (alt. 463 feet), crossing some small streams, which, like all else seen since leaving the Dunwah Pass, flow N. to the Ganges. Between Sheergotty and the Soane, occur many of the isolated hills of greenstone, mentioned above, better known to the traveller from having been telegraphic stations. Some are much impregnated with iron, and whether for their colour, the curious outlines of many, or their position, form quaint, and in some cases picturesque features in the otherwise tame landscape.
The road being highly cultivated, and the Date-palm becoming more abundant, we encamped in a grove of these trees. All were curiously distorted; the trunks growing zigzag, from the practice of yearly tapping the alternate sides for toddy. The incision is just below the crown, and slopes upwards and inwards: a vessel is hung below the wound, and the juice conducted into it by a little piece of bamboo. This operation spoils the fruit, which, though eaten, is small, and much inferior to the African date.
At Mudunpore (alt. 440 feet) a thermometer, sunk 3 feet 4 inches in the soil, maintained a constant temperature of 71.5 degrees, that of the air varying from 77.5 degrees, at 3 p.m., to 62 at daylight the following morning; when we moved on to Nourunga (alt. 340 feet), where I bored to 3 feet 8 inches with a heavy iron jumper through an alluvium of such excessive tenacity, that eight natives were employed for four hours in the operation. In both this and another hole, 4 feet 8 inches, the temperature was 72 degrees at 10 p.m.; and on the following morning 71.5 degrees in the deepest hole, and 70 degrees in the shallower: that of the external air varied from 71 degrees at 3 p.m., to 57 degrees at daylight on the following morning. At the latter time I took the temperature of the earth near the surface, which showed, surface 53 degrees, 1 inch 57 degrees, 2 inches 58 degrees, 4 inches 62 degrees, 7 inches 64 degrees.
The following day we marched to Baroon (alt. 345 feet) on the alluvial banks of the Soane, crossing a deep stream by a pretty suspension bridge, of which the piers were visible two miles off, so level is the road. The Soane is here three miles wide, its nearly dry bed being a desert of sand, resembling a vast arm of the sea when the tide is out: the banks are very barren, with no trees near, and but very few in the distance. The houses were scarcely visible on the opposite side, behind which the Kymore mountains rise. The Soane is a classical river, being now satisfactorily identified with the Eranoboas of the ancients.* [The etymology of Eranoboas is undoubtedly Hierrinia Vahu (Sanskrit), the golden-armed. Sons is also the Sanskrit for gold. The stream is celebrated for its agates (Soane pebbles), which are common, but gold is not now obtained from it.]
The alluvium is here cut into a cliff, ten or twelve feet above the bed of the river, and against it the sand is blown in naked dunes. At 2 p.m., the surface-sand was heated to 110 degrees where sheltered from the wind, and 104 degrees in the open bed of the river. To compare the rapidity and depth to which the heat is communicated by pure sand, and by the tough alluvium, I took the temperature at some inches depth in both. That the alluvium absorbs the heat better, and retains it longer, would appear from the following, the only observations I could make, owing to the tenacity of the soil.
2 p.m. Surface 104 degrees 22.5 inches 93 degrees 5 inches 88 degrees Sand at this depth 78 degrees. 5 a.m. Surface 51 degrees 28 inches 68 degrees
Finding the fresh milky juice of Calotropis to be only 72 degrees, I was curious to ascertain at what depth this temperature was to be obtained in the sand of the river-bed, where the plant grew.
Surface 104.5 degrees, 1 inch 102 degrees, 2 inches 94 degrees, 2.5 inches 90 degrees, 3.5 inches 85 degrees (Compact), 8 inches 73 degrees (Wet), 15 inches 72 degrees (Wet).