Imagine a lush forest with tree-ferns, their trunks capped by ribbon-like fronds. Conifers tower overhead, bearing triangular leaves almost sharp enough to pierce skin. Flowering plants are both small and rare.
You're standing in what is now...
The planet Mars is home to thick layers of clay that can span hundreds of feet. Since they need water to form, these outcrops have long been of interest to scientists looking for signs of past...
