There was nothing which we could see upon the shore which seemed to me so wonderful as the great sheet of water before us. Our numbers and our noise had frightened all living creatures away, and save for a few pterodactyls, which soared round high above our heads while they waited for the carrion, all was still around the camp. But it was different out upon the rose-tinted waters of the central lake. It boiled and heaved with strange life. Great slate-colored backs and high serrated dorsal fins shot up with a fringe of silver, and then rolled down into the depths again. The sand-banks far out were spotted with uncouth crawling forms, huge turtles, strange saurians, and one great flat creature like a writhing, palpitating mat of black greasy leather, which flopped its way slowly to the lake. Here and there high serpent heads projected out of the water, cutting swiftly through it with a little collar of foam in front, and a long swirling wake behind, rising and falling in graceful, swan-like undulations as they went. It was not until one of these creatures wriggled on to a sand-bank within a few hundred yards of us, and exposed a barrel-shaped body and huge flippers behind the long serpent neck, that Challenger, and Summerlee, who had joined us, broke out into their duet of wonder and admiration.
"Plesiosaurus! A fresh-water plesiosaurus!" cried Summerlee. "That I should have lived to see such a sight! We are blessed, my dear Challenger, above all zoologists since the world began!"
It was not until the night had fallen, and the fires of our savage allies glowed red in the shadows, that our two men of science could be dragged away from the fascinations of that primeval lake. Even in the darkness as we lay upon the strand, we heard from time to time the snort and plunge of the huge creatures who lived therein.
(The Lost World, Chapter XIV: Those Were the Real Conquests, Arthur Conan Doyle}