168 GEOLOGY. 



additional proof that its length was beyond all calculation. But 

 during its progress, deep seas and shallow seas, quiet seas and tur- 

 bulent seas, and vast bogs and swamps near to slightly elevated 

 land masses, in turn predominated. 



Vegetation. — The vegetation of the Carboniferous age was re- 

 markable for its luxuriance and its antique form. In organization 

 it was below the high modern types, but many of its forms were 

 exquisitely beautiful, synthetic and complex. 



The conifers that then existed, and which were the most advanced 

 in type of all the vegetable forms, nourished mainly on the uplands. 

 The most of them were closely related to Araucarian pines, which 

 still flourish in low latitudes and mainly south of the equator. The 

 fern family, of which a few diminutive representatives still linger 

 among us, culminated in that age, many species growing to the 

 dimensions of trees, and with a gracefulness and beauty unsur- 

 passed by any vegetable form at the present day. Many hundreds 

 of species flourished over the forming coal fields of the west. In 

 fact, one- half of the coal plants were probably ferns. The calamites 

 of that day, which grew to tree size, were also abundant. The 

 scouring rushes {Equisetae), which seldom reach over one or two 

 feet in height, are their modern representatives. Two great orders, 

 more abundant in the number of individuals than any others, the 

 Lepidodendrids and Sigillaria are no longer in existence. They, 

 along with the calamites, formed a large part of the material of the 

 coal. The Lepidodendrids had a dense bark, underneath which 

 was a dense mass of loose tissue, through the centre of which ran 

 a small cylinder with a distinct pith. Such a structure unfitted it 

 for anything like bearing timber, but adapted it most admirably, 

 when flattened down, for flakes of coal. The sigillarids, with 

 " trunks fluted like Corinthian columns," and ornamented with seal- 

 like impressions in vertical ranks, and " with few large branches 

 and long needle-like, tapering leaves," were unfitted for anything 

 except to minister to the beautiful and to make coal. It is remark- 

 able that in that distant past, long ages before man appeared, the 

 jungles and forests of the globe were as remarkable for beautiful 

 forms as the woodlands of to-day. The Deity, however, was there 

 to enjoy it. 



Animal Life. — Animal life during this age was abundant, though, 

 as in the vegetable kingdom, the forms were mostly antiquated. 

 One of the most abundant of all in individuals was the curious little 



