102 
Lancashire, 'a till wliicli is largely charged with blue lime- 
stone, and the matrix of which effervesces as freely as does 
the Bradford till. 
Resting upon an eroded surface of this lower till 'No. 1, 
lies another bed of blue clay 15 feet thick, but thinning 
out westwards near Manchester E-oad. It differs from the 
till No. 1 mainly in containing a large percentage of well- 
rounded small pebbles of Settle crystalline limestone ; a rock 
rarely seen in the lower till. The included limestones are all 
more or less ice-scratched, in most cases but faintly. Its 
appearance when first exposed is such as to be hardly dis- 
tinguishable from the till No. 1, but being of a looser and 
more open texture, it yields more readily to atmospheric 
action, and in a few weeks acquires a brownish tint. This is 
well seen at Shipley Fields, near the Red Beck, where a new 
siding on the Midland line shows the blue clay No. 2 resting 
upon an irregular surface of the till No. 1, from which it is 
clearly marked off by the difference in colour, save at one or 
two points where the two beds appear to shade into each other. 
Near tlie Shipley Fields bridge, in this same section, the 
lower till is seen to rest upon a pre- glacial river gravel, the 
pebbles all lying closely packed on their flat sides, with their 
long axes parallel to the direction of least resistance; evi- 
dently of fluviatile origin, and presenting, in fact, all the 
characteristics of the pre- glacial river gravels found in the 
Clyde Basin, as described by Mr. James Geikie in his " Great 
Ice Age." 
The blue clay No. 2, or upper till, is widely distributed 
within the Bradford basin. From Bowling Old Lane it 
crosses Bowling Park, rising, laden with limestone pebbles, 
to a height of 626 feet near Bierley Chapel ; or, following 
the East Brook, it may be traced from the Cattle Market, by 
Bowling Iron "Works, thence to Bradford Moor and down 
Leeds Road. It is largely developed in the valley through 
