Battle of Jaxartes question

[FarDarter]

In Steven Pressfield's novel The Afghan Campaign, which tells the story of a soldier in Alexander's campaign to put down Spitamenes' uprising in Sogdiana and Bactria, the book comes to, at one point, the Battle of Jaxartes. I have a question regarding a passage from the book, which describes the bows used by the Scythians.

The massive Scythian bow is wielded with one foot bracing it against the earth; it launches shafts half the size of javelins. Such missiles can fly a hundred yards with enough power to penetrate armor.

- pg. 195

I was curious; this seems to be describing a bow more similar to the longbow than the small Scythian recurve I found when I did more research. How possible is it to brace the bottom of a bow against the earth? A hundred yards seems somewhat short, considering Welsh longbows can do twice that. What can be made of this? A slip-up on the author's part, perhaps?

[Sean Manning]

Jack, that sounds like the description of Indian bows in Arrian, Indica 16. Arrian's source was probably Alexander's admiral Nearchus. I haven't heard of even the eastern Scythians using such long bows.

[Michael Kerr]

That type of bow would require one huge gorytus for the horse archer. I think in steppe warfare if the opposing armies engaged in a long distance archery duel that maybe some would dismount for better accuracy but I haven't heard of them using longbows like the one described in novel so maybe a bit of artistic licence by the author. I did enjoy book although author portrayed Massagetae & Saka as bloodthirsty savages who can't be trusted by their own allies but he did cover Battle of Jaxartes which I think was one of Alexander's underrated victories.
Regards
Michael Kerr