What evidence supports the idea that ancestors of whales once lived on land?

The wolf-sized animals ran about on land 50 million years ago. Other newly found fossils add to the growing picture of how whales evolved from mammals that walked on land. They suggest that early whales used webbed hind legs to swim, and probably lived both on land and in the water about 47 million years ago

the rocks are classified by the geological process they are formed by. the three main groups of rocks are igneous, metamorphic, and sedimentary. minerals are not they are classified under the chemical classes they are in. these groups include silicates, sulfates and carbonates.

i think this picture will you.