SALTER — A CHRISTMAS LECTURE ON COAL. 



123 



The Adiantites of the Old Red Sandstone, mentioned last month, 

 will be figured, and full descriptions given of it by the officers of the 

 Irish Geological Survey ; it is only, therefore, needful to give a sketch 



Fig. 3. — Osmunda regalis, living at Klllarney. Fig. 4. —Adiantites Hibernicus, fossil in 

 To show the terminal fructification of * Kilkenny. To show the lateral spikes 

 the living fern. of fructification in the fossil. 



figure of it here, especially as it does not actually belong to the coal, 

 though the same genus is found there. We must now pass on from 

 the ferns, and speak of the cylindrical stems so common in the coal. 



The other plants of the coal, which strike us most, are the fluted 

 stems called Sigillaria. They abound in all the shales, with every 

 kind of varying proportion in the patterns, which nevertheless is 

 of a regular and definite kind. It consists of longitudinal flutings, 

 generally in right lines, sometimes a little zigzag; and on the surface of 

 the flutings are scars, either round or somewhat kidney-shaped, or hex- 

 agonal — or even double ovals — or purse -shaped, nariower above than 

 below, and always with a couple of dots in them, which are the marks 

 of the vessels that supplied the leaves. For the scars are the bases 

 of the leaves, which are seldom found ; they are of a long shape, with 

 a rib down the middle. The stems vary from a few inches broad to 

 three feet in circumference, and specimens have been found that must 

 once have been sixty feet long. They are generally quite flat in the 

 shale, and often broken to pieces ; and they are, most generally, 

 covered with a coat of coal. The scars outside the coal-envelope are 

 not quite the same as those which show within, but pretty nearly so. 

 Our figure shows this (Fig. 5) . 



