210 THE OPEN BOOK OF NATURE 
plant growing healthily, but its flowers will be a few 
weeks before they appear. 
The rocks on either side of the stream are now 
of a different kind, and the valley opens out more 
widely, the scenery becoming more pastoral. We 
have left the volcanic region, and are amongst 
shales, limestones, and sandstones, still of Carbon- 
iferous age, but more recent than the ashes and 
lavas we have left behind us. These rocks belong 
to a higher horizon than the lavas, but they have 
been faulted down to such an extent that they now 
lie lower than the volcanic series. We had better 
use the geological hammer among the limestones, 
secure a few fossils, and then make our way home. 
I am tired and hungry, as I think you are, and we 
have seen enough to-day to set us thinking and 
inquiring for a long time to come. 
