Terrain wont collide

This code works for collisions with a wall but not with the Floor which is the Terrain.
I dont get an error but nothing happens when I drop a cube on the terrain unless it hits the wall?

void OnCollisionEnter(Collision collision) {

	if (collision.gameObject.name=="Wall")
	{
		Debug.Log("Hit Wall");
	}
	if (collision.gameObject.name=="Floor")
	{
		Debug.Log("Hit Floor");
	}
}

It now works when I renamed the terrain again