GEOLOGY AND MINERALOGY. 
67 
very zeolitic. In some places the zeolite occurs in bands and seams 
an eighth of an inch in thickness, but there is a marked absence of 
laterite beds when compared with the other parts of the Island. 
The sea has worn away the rocks to a distance of fifty feet or more 
at the beach, forming a plateau of dikes. The beach itself is formed 
of loose shingle, and the ground around is covered with fragments of 
a laminated phonolitic-looking dike. A greystone laminated or 
schistose dike, traversed by one purely augitic, may also be seen 
amongst the many varieties which occur at this spot. 
It is asserted that Manatees have been seen on shore at this 
portion of the coast ; if such be true they have proved their race 
t° be able navigators to have traversed the tortuous passages formed 
by the projecting dikes, which, running out into the sea, have 
desisted the destructive action of the waves, and stand up from the 
water like masses of crumbling masonry and tottering castle walls. 
The naturally wild, desert-like aspect of this portion of the 
Island is somewhat increased by the appearance here and there of 
the dead carcase of a sheep, and the wild scream of the sea fowl 
singled with the ceaseless voice of the ocean. 
To investigate the probable age of the Island, apart from the 
time occupied in building it up from its foundation to its summit,* 
lecourse must be had to an examination of the denuding action of 
the atmosphere upon the surface, and of the sea upon the coast line; 
and although no exact estimate can be arrived at, it is possible, by 
a calculation formed upon careful bases, to approximate near to it. 
The possession of a peculiar fauna and flora in itself points to 
very great antiquity, but its geological formation alone is sufficient to 
distinguish it as perhaps the most ancient volcanic production of its 
character. 
It may even still be startling to some who cling to the 
idea that the world is no older than six thousand years, to be in- 
formed that the Island is a veteran of at least eight or ten times 
that period ; and that there it has stood, alone, weather-beaten and 
Worn, unvisited perhaps by any save wild seabirds, through hun- 
dreds of centuries before the birth of man. But, be this as it may, 
We are bound to read the Book of Nature aright, knowing well that 
* At St. Helena sixty or seventy distinct flows of lava can even still be counted, and if these 
occurred at intervals of a century, it would give a period of six or seven thousand years for 
he building up of the Island. 
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