Right, the rail clamps. 'Platform' I called it... my fingers are better suited to a keyboard than tools I'm afraid. Not much of a mechanical bent.
What was the post made of?
I'd have to think the post was steel, it was the stock post on a Trek 7100 hybrid.
Are you ok now though?
I'm OK, thanks, except for my back which is really stiff. The more I think about it, the more I wonder how I didn't crash... must have built the legs a little commuting over the past year.