The River Anyder riseth four and twenty miles above Amaurote, out of a little spring: but being increased by other small floods and brooks that run into it: and, among others, two somewhat bigger ones. Before the City, it is half a mile broad (hardly so much now as it was in former days, being pent in and straitened to a narrower space, by the later buildings on each side): and further, broader. By all that space that lieth between the Sea and the City, and a good sort of land also above, the water ebbs and flows six hours together, with a swift tide; when the sea flows in to the length of thirty miles, it fills all the Anyder with salt water, and drives back the fresh water of the river; and somewhat further, it hangeth the sweetness of fresh water with saltness: but a little beyond that, the river waxeth sweet, and runneth foreby the City fresh and pleasant; and when the sea ebbs and goes back again, this fresh water follows it almost to the very fall into the sea. They have also another river, which indeed is not very great, but it runneth gently and pleasantly: for it riseth even out of the same hill that the City standeth upon, and runneth down slope through the midst of the City into Anyder. And because it ariseth a little without the City, the Amaurotians have enclosed the head spring of it with strong fences and bulwarks; and so have joined it to the City: this done, to the intent that the waters should not be stopped nor turned away, nor poisoned, if their enemies should chance to come upon them. From thence the water is derived and brought down in channels or brooks divers ways into the lower parts of the city. Where that cannot be done by reason that the place will not suffer it, then they gather the rain water in great cisterns which doth them as good service. Then next for the situation and walls. That it stood by the side of a low hill, in fashion almost square. The breadth of it began a little beneath the top of the hill, and still continued by the space of two miles, until it came to the river Anyder. The length of it, which lieth by the river-side, was somewhat more. The City is compassed about with an high and thick wall, full of turrets and bulwarks. A dry ditch, but deep and broad and overgrown with bushes, briers, and thorns, goeth about three sides or quarters of the City. To the fourth side, the river itself serveth for a ditch.