UNDER THE APPLE-TREES 
dot my native fields, there is here and there a black 
sheep — a rough-coated rock much darker than 
the rest, which the farmers call firestone, mainly, I 
suppose, because it does not break or explode in 
the fire. It is a kind of conglomerate, probably 
what the geologists call breccia, made up of the con- 
solidated smaller fragments of older crushed rocks. 
The material of which it is composed is of unequal 
hardness, so that it weathers very rough, present- 
ing a surface deeply pitted and worm-eaten, which 
does not offer an inviting seat. These rocks wear a 
darker coat of moss and lichens than the others and 
seem like interlopers in the family of field boulders. 
But they really belong here; they have weathered 
out of the place strata. Here and there one may find 
their dark worm-eaten fronts in the outcropping 
ledges. They were probably formed of the coarser 
material —a miscellaneous assortment of small 
thin water-worn fragments of rocks and mud and 
coarse sand — that accumulated about the mouths 
of the streams and rivers which flowed into the old 
Devonian lakes and seas. They are not made up of 
thin sheets like the other rocks, and seem as if made 
at a single cast. They are as rough-coated as alli- 
gators, and do not, to me, look as friendly as their 
brother rocks. They stand the fire better than other 
stone. The huge stone arch in my father’s sugar 
bush, in which the great iron kettles were hung, was 
largely built of these stones. I think the early set- 
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