188 EXTINCT MONSTERS 
from lizards, possessing, as usual, four legs; that some primitive 
form of lizard with very small legs appeared on the scene, and 
found that it could better move along by wriggling its body and 
pushing with its ribs than by walking. So, in course of time, 
a race of lizards without legs arose; these, by Natural Selection, 
and perhaps other means, became more and more elongated, so 
that they could move faster than their ancestors, and glide out 
of harm’s way more effectually. Thus was the snake evolved 
from a lizard. 
Now, in the great geological museum of the stratified rocks, 
there have been discovered skeletons of marine reptiles, which 
propelled themselves chiefly by means of their tails and elongated 
bodies, rather than by their limbs. The limbs were not discarded 
entirely as in the case of the serpents, but were useful in their 
way as the fins of fishes are. Perhaps, therefore, we may be 
justified in calling these ancient monsters, sea-serpents, in con- 
sideration of their long thin bodies; for they certainly would be 
called by that name if now living, and their skulls are very much 
like those of a modern lizard known as Varanus. 
Strictly speaking, they were not serpents, but more or less like 
some of the extinct saurians described in Chap. V. The name, 
however, has been adopted by geologists, and is useful in so 
far as it serves to remind us of their very peculiar shape and 
structure. Remains of these strange creatures have been found 
both in Europe, North and South America, and New Zealand. 
One of the earliest discoveries of remains of a fossil sea-serpent 
was made by M. Hoffmann, a Dutch military surgeon, in the year 
1770. Maestricht, a city in the interior of the Netherlands, 
situated in the valley of the Meuse, stands on certain strata of 
limestone and sandstone, belonging to the Upper Chalk. Exten- 
sive quarries have, for many centuries, been worked in the 
