Strange shapes in the Martian terrain are a common sight, and always upon viewing the latest images I spot what looks vaguely like earthly forms.
My belief has always been that Mars was quite different 66 million years ago. I see a solar system pummeled in completeness. Earth experienced a planet-wide catastrophe changing forever the environment but remaining alive while the other planets such as Mars was shattered.
I will not dismiss the theory that even Venus was in another orbit at the time. Saturn gained rings though the current time element is stated as more like 100 MYA. Our solar system was rearranged and what we see today is more like what is left.
In short, the scars of many millions of years ago is evident all around us and accepted as a natural result of earthly evolution when the degradation wrought by cosmic circumstances remains.
This is what is left, not all there always was.