[Rumil]

Hello all,

yes not quite decided whether the description of Orthanc as being carved out of a single piece is metaphor, simile or straight-up!

Interesting to hear that marble is too friable, like the idea of basalt, though some sort of white 'basalt-il' for Minas Tirith perhaps, though perhaps the clue is that it was made out of the White Mountains. Was thinking of some sort of concrete sort of thing, but reinforced ferro-concrete is not very Middle Earth really.

Interesting thought about extinct caldera, could explain the Ring of Isengard? Alternatively perhaps a meteorite crater? So Orthanc = iridium steel ??? OK getting silly now, perhaps more 'in-book' - a shard of one of the two lamps?

Anyway there seem to have been similarities in construction of the Deeping Wall, Orthanc, Minas Tirith, Minas Morgul, Towers of the Teeth and Cirith Ungol, all made by the Numenoreans in their days of power.

More prosaically the Rohirrim had old forts on the far bank of the Isen, but these seem to have been simple ditch-and-bank constructions, with probably a pallisade on top, now overgrown and decayed.

There seems to have been some really long wall (like Hadrian's?) around Arthedain, the hobbits cross it after they leave Tom on their way to Bree. Also the chain of forts and watchtowers on the Weather Hills, perhaps adding up to some 'Roman limes'-type system? Probably these would be ordinary stone and mortar, being built long after the decay of Numenorean craft/tech.

Noticed a few instances of hedges being used for defence, the High Hay, Bree and Caras Galadhon.