300 
WILLIAMSON: JOHN WILLIAMSON. 
by various agencies, liberated these harder stones. Others of them 
were frag-ments of metamorphosed stratified rocks. The original 
home of most of these stones was Scotland and other Northern 
regions, whence they were brought southward by the several glacial 
agencies to which the Drift or boulder clays of Yorkshire coast owed 
their existence. Such of these clays as were within the reach of the 
sea were undergoing constant waste, causing the shore to be strewed 
with the hard shingle with which the clays abound. The gravel o^ 
the bay extending northward from Whitby to the village of Sandsend 
were formerly rich in these " pebbles," as the bay afforded a 
convenient route for pedestrians between Lyth and Whitby, it was 
frequently crossed by the young gardener, who was too observant 
not to detect such specimens as were worth collecting; his connection 
with the jeweller's family would give him an additional interest in 
these stones, since they were in demand to be manufactured into 
brooches and other ornaments. Many of the agates were exquisitely 
beautiful; but one large ifocAa, by whom collected is not now known, 
stood out from the rest under the name of the York Minster agate, 
because of the resemblance which the sections of it have to the 
coloured glass of the Minster windows. A slice of this fine stone is 
still, I believe, in the Museum of the Scarborough Philosophical 
Society. 
But Williamson's attention could not long be limited to these 
transported pebbles. As is well-known, the lofty cliffs and flat scars 
extending for miles north and south of Whitby, mainly consist of 
Liassic beds extremely rich in fossil remains ; but those fossils are 
now much less easily obtained than was the case even in my own 
earlier days. Whether conspicuously exposed, or embedded in 
hard rounded concretions, they then stood out from the softer tide- 
worn strata which enclosed them in great numbers. An hour 
or two spent on the shore below the Lyth Alum Works, would 
then have furnished more superb fossils than we could have carried 
away with us. Hard nodules abounded, half embedded in the shale. 
Some of these contained fine specimens of the Ammonites annulatus 
and communis. Others enclosed the large chambered phragmocones 
of Belemnites, the guards of which protruded from one end of the 
