The chief city of northern Media, which bore in later times the names of Gaza, Gazaca, or Canzaca, is thought to have also been called Ecbatana, and to have been occasionally mistaken by the Greeks for the southern or real capital.  The description of Herodotus, which is irreconcilably at variance with the local features of the Hamadan site, accords sufficiently with the existing remains of a considerable city in the province of Azerbijan; and it seems certainly to have been a city in these parts which was called by Moses of Chorene “the second Ecbatana, the seven-walled town.”  The peculiarity of this place was its situation on and about a conical hill which sloped gently down from its summit to its base, and allowed of the interposition of seven circuits of wall between the plain and the hill’s crest.  At the top of the hill, within the innermost circle of the defences, were the Royal Palace and the treasuries; the sides of the hill were occupied solely by the fortifications; and at the base, outside the circuit of the outermost wall, were the domestic and other buildings which constituted the town.  According to the information received by Herodotus, the battlements which crowned the walls were variously colored.  Those of the outer circle were white, of the next black, of the third scarlet, of the fourth blue, of the fifth orange, of the sixth silver, and of the seventh gold.  A pleasing or at any rate a striking effect was thus produced—­the citadel, which towered above the town, presenting to the eye seven distinct rows of colors.

If there was really a northern as well as a southern Ecbatana, and if the account of Herodotus, which cannot possibly apply to the southern capital, may be regarded as truly describing the great city of the north, we may with much probability fix the site of the northern town at the modern Takht-i-Suleiman, in the upper valley of the Saruk, a tributary of the Jaghetu. [Plate I., Fig. 3.] Here alone in northern Media are there important ruins occupying such a position as that which Herodotus describes.  Near the head of a valley in which runs the main branch of the Saruk, at the edge of the hills which skirt it to the north, there stands a conical mound projecting into the vale and rising above its surface to the height of 150 feet.  The geological formation of the mound is curious in the extreme.  It seems to owe its origin entirely to a small lake, the waters of which are so strongly impregnated with calcareous matter that wherever they overflow they rapidly form a deposit which is as hard and firm as natural rock.  If the lake was originally on a level with the valley, it would soon have formed incrustations round its edge, which every casual or permanent overflow would have tended to raise; and thus, in the course of ages, the entire hill may have been formed by a mere accumulation of petrefactions.  The formation would progress more or less rapidly according to the tendency of the lake to overflow