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THE NATURE BOOK 



VOLUTA—A BEAUTIFUL FOSSIL SHELL FROM 

 THE BARTON CLAY. 



fordshire an interesting set of rocks come 

 above the Silurian formation, and are 

 known as the Old Red Sandstone. The 

 rocks of the Old Red Sandstone apparently 

 were formed in great inland lakes not 

 unlike the Lake Superior of to-day. Hugh 

 Millar has made this formation famous 

 by his charming book entitled, " The 

 Old Red Sandstone." How strange in 

 appearance the creatures which dwelt in 

 these great lakes must have been, cannot 

 be better described than in the words of 

 Hugh Millar himself : " Creatures whose 

 very type is lost, fantastic and uncouth, 

 and which puzzle the naturalist to assign 

 them even their class ; boat-like animals, 

 furnished with oars and a rudder ; fish 

 plated over, hke the tortoise, above and 

 below, with a strong armour of bone, 

 and furnished with one rudder-like fin ; 

 other fish less equivocal in their form, 

 but with the membranes of their fins 

 thickly covered with scales ; creatures 

 bristling over with thorns ; others gUsten- 

 ing in an enamel coat as if beautifully 

 ja-panned. All the forms testify of a remote 

 antiquity — of a period whose fashions 

 have ])assed away." 



\Vc now come to one of the most 

 important and interesting geological 



periods in the Earth's history, the Car- 

 boniferous period, during which our coal- 

 fields were forming. It was an age of 

 luxuriant vegetation, in which the land 

 was covered with vast forests of m.ost 

 extraordinary appearance, composed of 

 giant tree-ferns, Club-mosses, and Horse- 

 tails of majestic proportions, and great 

 monkey-puzzle trees {Araiicarias). From 

 our British Coal strata no less than 130 

 species of ferns have been obtained, yet 

 to-day there exist in the whole of Europe 

 but some sixty-seven indigenous species. 

 Of the giant Club-mosses, whose trunks 

 frequently exceeded fifty feet in length, 

 some forty species have been discovered. 

 Their descendants, the Club-mosses of to- 

 day, are most abundant in tropical 

 climates, are diminutive in size, and usually 

 creep on the ground, though a few. like the 

 Lycopodiinn densiim of New Zealand, 

 stand erect and attain a height of nearly 

 three feet. The Horse-tails {Eqnisites 

 and Calamites), whose stems were five 

 inches or more in diameter and eight 

 feet in height, grew in dense companies 

 on the sand or mud flats, in much the 

 same manner as their dwarf descendants 

 of to-day. In the sluggish rivers and 

 swamps dwelt weird amphibious animals 

 of predaceous character, ranging in size 

 from a few inches to some eight feet. 

 Fishes swarmed in the waters of the period ; 

 many were armed with powerful conical 

 teeth, while others possessed massive 

 ])alates adapted for crushing or cutting 

 their food. In the estuaries vast numbers 

 of a species of fresh-water mussel existed, 

 their shells, somewhat resembling the form 

 of their modern representatives. Lace- 

 wing flies flitted through the dark 



KKOM 1 HE OOLITE FORMATION. 



