216 
roads along the whole line of their extent, under the name of 
" grey stones," and in some places have been burnt for lime. 
The thickness of the three beds amounts together to about six 
yards. To the north of Ellerker, the middle term of the 
series disappears, and the formation consists of sandy beds 
in the upper portion, and oolitic stone in the lower. The 
shells characteristic of this rock aire Terebratula spinosa, 
Turritella, Lima proboscidea, Trigoniae. 
The Lias is the lowest bed in the oolitic series, and which 
occupies a considerable portion of country in the district 
described in the Report. From Fangfoss, by Pocklington, 
where it forms a lofty escarpment behind the town, it extends 
to Londesborough, Goodmanham, and Market Weighton, 
producing at these places and around Kilnwick Percy, some 
of the best grazing pastures in the country. The beds usually 
presented consist of a mass of blue and yellow clay, varying 
from 50 to 60 feet in thickness ; and the soil partakes greatly 
of the subsoil, the gradation from one to the other being only 
marked by the colour : indeed, as a general rule, the clay 
soils are seldom intermixed in Yorkshire with sand or debris, 
although frequently they are covered by it, and have boulders 
embedded in them. In the Lias clay beds there are, however, 
several loose stony beds, seldom approaching to the character 
of rock, which in places come to the surface, and form very 
excellent land. Upon the terrace to the east of Pocklington 
they have been partially quarried for road material, but from 
want of continuity have been only dug in circular pits out 
of the surface. From North Cliff to within a field's-length 
of North Cave, these stony beds form some of the best arable 
land in the neighbourhood, yielding excellent and heavy crops 
of all descriptions. To the east of this good land, which 
extends between North Cliff and North Cave, the upper 
stony beds of the lias have been washed away, and around 
Houghton plantation and Houghton common a great extent 
