Sweden.)
Next in the descending order are the shales and sandstones in which the
quartzose rocks called Stiper-Stones in Shropshire occur. Originally these
Stiper-Stones were only known as arenaceous quartzose strata in which no organic
remains were conspicuous, except the tubular burrows of annelids (see Figure
563, Arenicolites linearis), which are remarkably common in the Lowest Silurian
in Shropshire, and in the State of New York, in America. They have already been
alluded to as occurring by thousands in the Silurian strata unconformably
overlying the Cambrian, in the mountain of Queenaig, in Sutherlandshire (Figure
82). I have seen similar burrows now made on the retiring of the tides in the
sands of the Bristol Channel, near Minehead, by lob-worms which are dug out by
fishermen and used as bait. When the term Silurian was given by Sir R.
Murchison, in 1835, to the whole series, he considered the Stiper-Stones as the
base of the Silurian system, but no fossil fauna had then been obtained, such as
could alone enable the geologist to draw a line between this member of the
series and the Llandeilo flags above, or a vast thickness of rock below, which
was seen to form the Longmynd hills, and was called "unfossiliferous graywacke.
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