List all evidence, which supports the idea that before the tertiary period, there was a huge sea where the himalayas now stands.

The Tertiary Period marks the beginning of the Cenozoic Era. It began 65 million years ago and lasted more than 63 million years, until 1.8 million years ago. The Tertiary is made up of 5 epochs :

The Paleocene Epoch - 65 to 54 million years ago
The Eocene Epoch - 54 to 38 million years ago
The Oligocene Epoch - 38 to 24 million years ago
The Miocene Epoch - 24 to 5 million years ago
The Pliocene Epoch- 5 to 1.8 million years ago

Each epoch has unique characteristics for climate and geography. The plants and animals changed from epoch to epoch also.

In the early 1800’s a system for naming geologic time labeled only four periods. They were named using the Latin forms of numbers for first, second, third and fourth. The word tertiary means “third.” It was the third period in this system. Today, we use a different system, but the name Tertiary is still common for the first part of the Cenozoic Era.