No, that Silurian was Alaya.
Actually, Alaya was the Silurian from "The Hungry Earth" that was killed by Ambrose. That leaves Restac, her twin sister, to lead the charge against the Silurians remaining underground in "Cold Blood".\
just the same actor, different character
Vastra was a new character, introduced in "A Good Man Goes to War". Of course, she might be back, later.