352 MR. TATE ON POLISHED AND SCRATCHED ROCKS, 
The railway cutting near the Lesbury station exhibited a section 
having at the base four distinctly stratified gravel beds, consisting 
of rolled smooth stones, chiefly porphyries, limestones, and sand- 
stones, about the size of ordinary paving stones ; above these was 
a bed of stiff clay, 8 feet high, without boulders ; and above this 
again was another bed of clay, 8 feet high, with large boulders. 
In this section, as well as in several others where gravel beds are 
seen, the layers were arched, dipping away on both sides from a 
central axis. 
The gravel beds differ from the boulder clay bed as to the source 
of their rocks ; in the former, the rocks are chiefly those which are 
not found, zm situ, in the immediate neighbourhood : in the latter 
the boulders are chiefly of local origin. In the gravel beds are 
red and dark coloured porphyries, hornblendic, and quartz rocks, 
such as are found in the Cheviots, mingled with a smaller number 
of sandstones, and a very few pebbles of limestone and coal: all 
of them are rounded and water-worn. The Hawkhill boulder 
clay contained a number of blue limestone blocks from 6 inches to 
18 inches in diameter, basalts from 6 inches to 2 feet in diameter, 
and sandstones and shales generally of a small size ; these rocks 
are the same as appear, 77 situ, in the neighbourhood. There were, 
however, a few rocks which cannot, as yet, be identified as of local 
origin ; among these was a block of light cream coloured and fine 
grained, almost compact, limestone, containing 18 cubic feet, not 
rounded, but polished and scratched on the under surface. A 
similar rock, in situ, I have observed at Beal, at a distance of 
20 miles N. by W. from the quarry. Another limestone of a 
bright red colour, which is not uncommon in the boulder clay 
further north, was also found in the Hawkhill Clay ; the original 
source of this rock I have not been able to discover—it is said to 
occur in Scandinavia ; red Limestones are found in the West of 
Scotland and in Herefordshire, but their colour is much duller ; it 
may, however, be of local origin as the fossils show, that it belongs 
to the mountain limestone, and as, moreover, limestones, when 
near to basalts, are, as 1 have observed, occasionally red in colour; 
these fragments may therefore have come from some bed in 
the neighbourhood which had derived its peculiar character from 
