170 THE OPEN BOOK OF NATURE 
side of the hill where the rock is quite polished by 
the gradual sliding down of the sandstone. It is 
called a slickenside. 
When I was last here I saw the impression of 
a Lepidodendron (see p. 98) on a sandstone surface. 
See, it is here yet, quite undisturbed, as T was afraid 
it might have been, and beautifully distinct. The 
scalelike markings can be seen clearly. You may 
be able to find some pieces of Calamites (p. 98), 
Sigillaria (p. 101), and Stegmaria (p. 101) amongst 
that heap of stones which have been recently 
quarried. It would be nice to get some good 
specimens for the museum at home, our collec- 
tion of Carboniferous plant remains not being, at 
present, as good as it might be. 
What, half-past twelve o’clock! The time has 
passed far too rapidly. I expect you are as hungry 
as I am, so we will make this the end of the present 
chapter of our ramble. We can discuss a few 
matters while we take our lunch, and begin another 
chapter when we have rested and refreshed the 
inner man. 
