Vit THE ANTIQUITY AND ORIGIN OF MAN 425 
The island containing these remarkable works of art has 
only an area of about thirty square miles, or considerably less 
than Jersey. Now, as one of the smallest images (eight feet 
high) weighs four tons, the largest must weigh over a 
hundred tons, if not much more; and the existence of such 
vast works implies a large population, abundance of food, and 
an established government. Yet how could these coexist on 
a mere speck of land wholly cut off from the rest of the 
world? Mr. Mott maintains that these facts necessarily 
imply the power of regular communication with larger islands 
or a continent, the arts of navigation, and a civilisation much 
higher than now exists in any part of the Pacific. Very 
similar remains in other islands scattered widely over the 
Pacific add weight to this argument. 
North American Earthworks 
The next example is that of the ancient mounds and 
earthworks of the North American continent, the bearing of 
which is even more significant. Over the greater part of the 
extensive Mississippi valley, four well-marked classes of these 
earthworks occur. Some are camps, or works of defence, 
situated on bluffs, promontories, or isolated hills; others are 
vast inclosures in the plains and lowlands, often of geometric 
forms, and having attached to them roadways or avenues 
often miles in length; a third are mounds corresponding to 
our tumuli, often seventy to ninety feet high, and some of 
them covering acres of ground; while a fourth group consists 
of representations of various animals modelled in relief on a 
gigantic scale, and occurring chiefly in an area somewhat to 
the north-west of the other classes, in the plains of Wisconsin. 
The first class—the camps or fortified inclosures—re- 
semble in general features the ancient camps of our own 
islands, but far surpass them in extent. Fort Hill, in Ohio, 
is surrounded by a wall and ditch a mile and a half in length, 
part of the way cut through solid rock. Artificial reservoirs 
for water were made within it, while at one extremity, ona 
more elevated point, a keep is constructed with its separate 
defences and water-reservoirs. Another, called Clark’s Work, 
in the Scioto valley, which seems to have been a fortified 
town, incloses an area of 127 acres, the embankments measur- 
