5 0 BILLINGEN AND THE HILLS NEAR IT. [Chap. III.
mixed with marl-slate. This bed is seen very distinctly as you ascend
the hill from Reseta, which is nearly at the bottom o f the last little
hill ; but as a great part o f the hill in this place is covered with grass,
and even with corn, and the ascent is very unequal, small flat terraces
intervening here and there, I was not able to determine the thickness
with any thing like accuracy. Gyllenhall states the thickness o f the
bed of marl-slate to be four feet. In the part of the hill which I
examined, there was no possibility o f determining the point ; because
the greatest part of it was covered with grass.
The uppermost rock o f all is exactly similar to thè rock which
crowns the summit of Hunneberg. Like it I consider it as a greenstone
; it has a columnar form and many of its pillars have tumbled
down and strewed the whole side of the hill. It was very easy to
examine it; but I was stopped by à circùmstancë which was sufficiently
provoking ; it was so hard, and the edges o f it so rounded by
the weather, that I was not able to break off good specimens. Though
I spent two hours in the attempt, I came away at last without satisfying
myself completely. This trap covering is very small when compared
with the top of Hunneberg; it does not extend in length above
a quarter o f a mile, and its thicknèss cannot much exceed 200 feet.
Billingen, and the cluster of little hills u p o n the south side of it,
are composed of the very same beds with Kinnekiille, lying in the vëry
same order. The quantity of greenstoné upon the top o f ¿Billingen is
considerable ; that upon the others is small. This will be best judged
o f by casting the eye upon the annexed geognostic map of West
Gothland, where the different beds are distinguished by different
colours.
I did not measure the height of any of these hills; their distance
from the lake and their very small apparent elevation rendered such a
measurement o f little value, unless I had posséésed the means of
making an observation at the same time on the banks of the lake, and
on the top of Billingen. This was impossible, because I was possessed
of only one portable barometer. From the top of Kiijnëcülle these
kills appeared scarcely at all elevated above the surrounding country -