FREE BOOKS

Author's List




PREV.   NEXT  
|<   128   129   130   131   132   133   134   135   136   137   138   139   140   141   142   143   144   145   146   147   148   149   150   151   152  
153   154   155   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171   172   173   174   175   176   177   >>   >|  
the form in one piece, save that there is a certain degree of flatness common to all, bears no resemblance to the form in another. Some of the recent Astreae are of great beauty when inhabited by the living zoophites whose skeleton framework they compose. Every polygonal star in the mass is the house of a separate animal, that, when withdrawn into its cell, presents the appearance of a minute flower, somewhat like a daisy stuck flat to the surface, and that, when stretched out, resembles a small round tower, with a garland of leaves bound round it atop for a cornice. The _Astrea viridis_, a coral of the tropics, presents on a ground of velvety brown myriads of deep green florets, that ever and anon start up from the level in their tower-like shape, contract and expand their petals, and then, shrinking back into their cells, straightway became florets again. The Lower Lias presented in one of its opening scenes, in this part of the world, appearances of similar beauty widely spread. For miles together,--we know not how many,--the bottom of a clear shallow sea was paved with living Astreae: every irregular rock-like coral formed a separate colony of polypora, that, when in motion, presented the appearance of continuous masses of many-colored life, and when at rest, the places they occupied were more thickly studded with the living florets than the richest and most flowery piece of pasture the reader ever saw, with its violets or its daisies. And mile beyond mile this scene of beauty stretched on through the shallow depths of the Liasic sea. The calcareous framework of most of the recent Astreae are white; but in the species referred to,--the _Astrea viridis_,--it is of a dark-brown color. It is not unworthy of remark, in connection with these facts, that the Oolitic Astrea of Helmsdale occurs as a white, or, when darkest, as a cream-colored petrifaction; whereas the Liasic Astrea of Skye is invariably of a deep earthy hue. The one was probably a white, the other a dingy-colored coral. The Liasic bed of Astreae existed long enough here to attain a thickness of from two to three feet. Mass rose over mass,--the living upon the dead,--till at length, by a deposit of mingled mud and sand,--the effect, mayhap, of some change of currents, induced we know not how,--the innumerable polypedes of the living surface were buried up and killed, and then, for many yards, layer after layer of a calciferous grit was piled over them. The
PREV.   NEXT  
|<   128   129   130   131   132   133   134   135   136   137   138   139   140   141   142   143   144   145   146   147   148   149   150   151   152  
153   154   155   156   157   158   159   160   161   162   163   164   165   166   167   168   169   170   171   172   173   174   175   176   177   >>   >|  



Top keywords:
living
 

Astrea

 

Astreae

 

beauty

 

Liasic

 
florets
 
colored
 

surface

 
stretched
 

viridis


shallow

 

presented

 
recent
 

presents

 
separate
 

framework

 
appearance
 
innumerable
 

polypedes

 

currents


depths

 

referred

 

species

 

buried

 

calcareous

 

induced

 

calciferous

 

flowery

 

pasture

 

reader


richest

 
thickly
 

studded

 

violets

 

unworthy

 
daisies
 

killed

 
Helmsdale
 

existed

 
length

mingled
 

deposit

 
thickness
 
attain
 

change

 

occurs

 
darkest
 

Oolitic

 
connection
 

petrifaction