260 GILLIGAX : ALLUVIAL DEPOSITS AT WOODLESFORD, ETC. 
occurring in the basin of the River Aire. The quartz showed the devel- 
opment of new crystal faces just as it so frequently does in the Millstone 
Grit : the felspar was quite fresh and was extremely abundant in some 
layers. Some ot the bands of sand were coloured black in consequence 
of the presence of manganese dioxide, while other bands were deeply 
stained by the oxides of iron. 
In a brief account *of these deposits given in 1911 to the Leeds 
Geological Association, it was stated by the authors that very few 
garnets and zircons were found in these sands. The sands had then only 
been examined in bulk under the microscope, and no separation of 
heavy minerals had been carried out. This has since been effected 
by means of a Sollas bottle and Sonstadt's solution, with the results 
given below, the minerals being named in the order of their abundance. 
Sand from different horizons and various parts of the excavation have 
been examined — including the sand mixed with the gravels- — and no 
perceptible differences have been made evident, except that there was 
a greater abundance of garnets in the sands from the gravel beds : — 
(1) Garnet, in abundance in some of the beds. 
(2) Zircon, very abundant in all separations. 
{']) Leucoxene, often with ilmenite in the interior and anatase or 
rutile as secondary outgrowths. 
(4) Tourmaline, chiefly brown, but blue and purple also occur. 
(5) Monazite, several grains in each separation. 
(6) Barytes, a few grains in the gravels. 
There was often a quantity of clay-ironstone present. Xenotime 
is possibly also to be added to the list, as many grains were found 
resembling zircon except in the fact that they were pink in colour 
or clouded. 
These minerals are in all respects similar to those found in the 
Millstone Grit and Coal Measure sandstone and shales, and will be 
fully described in my paper upon the Millstone Grit of Yorkshire. 
Clays. 
As shown in the section exposed at the engine house, two beds of 
clay occur, separated by a varying thickness of sand and gravel. Whilst 
* "Alluvial Deposits at Woodlesford," by A. Gilligan, B.Sc, and 
E. L. Hummel, B.Sc. Trans. Leeds Geological Assoc., pt. xvi., p. 24. 
