Sorry guys, I don't have set in my mind exactly what the earmarks are for asteroids, meteorites, comets, etc. etc. All I was saying is that I believe it was basically "something" from "space" that hit the earth.
Indeed, "it" may have vaporized on (or before actual) impact in Tunguska. Makes perfect sense to me.
I vaguely recall the plant mutation in Tunguska, Ghostdancer, can you refresh me?
Kell