The main axis of the structure extends, therefore, from north to south.

The principal gateway opens in the western wall, not far from the northwest corner: but there would appear to have been two smaller gates, one in the south front, and one in the east.

The walls, which now stand from twenty-four to thirty-six feet high, have lost somewhat of their original height.

They are about six feet thick at the top.

They were not built all together in uniform layers, but in huge vertical panels, easily distinguished by the arrangement of the brickwork.