It came to an end some eighty million years ago.
In the world to-day the genera of Reptiles are paratively few and their distribution is very limited.
They are more various, it is true, than are the few surviving members of the order of the amphibia whibsp;onbsp;in the Carboniferous period ruled the world.
We still have the snakes, the turtles and tortois (the Chelonia), the alligators and crocodiles, and the lizards.
Without exception they are creatures requiring warmth all the year round; they ot stand exposure to cold, and it is probable that all the reptilian beings of the Mesozoibsp;suffered under the same limitation.
It was a hothou fauna, living amidst a hothou flora.
It endured no frosts.
But the world had at least attained a real dry land fauna and flora as distinguished from the mud and s fauna and flora of the previous heyday of life upon earth.
All the sorts of reptile we know now were mubsp;more abundantly reprented then, great turtles and tortois, big crocodiles and many lizards and snakes, but in addition there was a number of ries of wonderful creatures that have now vanished altogether from the earth.
There was a vast variety of beings called the Dinosaurs.
Vegetation was now spreading over the lower levels of the world, reeds, brakes of fern and the like; and browsing upon this abundanbsp;came a multitude of herbivorous reptiles, whibsp;incread in size as the Mesozoibsp;period ro to its climax.
Some of the beasts exceeded in size any other land animals that have ever lived; they were as large as whales.
The Diplodobsp;egii for example measured eighty-four feet from snout to tail; the Gigantosaurus was even greater; it measured a hundred feet.
Living upon the monsters was a swarm of ivorous Dinosaurs of a corresponding size.
One of the, the Tyrannosaurus, is figured and described in many books as the last word in reptilian frightfulness.