INFERIOR OOLITE : LINCOLN. 
219 
6. Fine-grained, buff and shelly, lime- FT. ITS. 
stones, more or less oolitic, with 
Nerincea : some of these layers 
resemble Stamford Marble : they 
include the Silver Bed, which is 
regarded as the best local building- 
stone : it was used in Lincoln 
Cathedra] - - 6 
The numbers are given- for comparison of the strata with those noted at 
the Greetwell road quarry (p. 217). The Silver Bed has been use-I for 
chimney -pieces and floors of passages. 
A band of ironstone, 4 ft. 6 in. thick, occurs above the Upper 
Lias north-east of Lincoln, where it has been exposed in the 
brickyard of Messrs--. Swan Bros, and Bourne. 
Further north exposures are not common, but at Glentworth 
and Hemswell the Basement Beds seem to be considerably thicker. 
The Lower Estuarine Series is represented by grey and brown 
loam, sand, and clay with ironstone nodules in the upper part ; 
and it has been exposed to a depth of 10 or 15 feet. The lower 
beds of brown sandy rock, that represent the Northampton Sand, 
were estimated by Mr. Ussher to be from 10 to 15 feet thick. 
Along the escarpment north of Lincoln, the lower beds of the 
Lincolnshire Limestone have been quarried in many places. 
They comprise creamy and oolitic limestones with thin bands of 
clay ;* but they afford no sections of particular interest. Nor 
have we much evidence for tracing on the clay-band that further 
north overlies the Kirton Beds. (See Fig. 62.) 
Mr. Dalton states that "In the Nettleham .Road, rather more 
than half a mile from the Cathedral, a small quarry now aban- 
doned shows, under 5 feet of rubble, a band of fossiliferous shaly 
marl nearly 3 feet thick overlying 6 feet of limestone/' No such 
bed appears in the railway-cutting west of Greetwell, which 
exposes about 30 feet of the beds, but this " thick marl band " 
overlaid a similar thickness of stone-beds where seen on the 
Nettleham road. 
The exposures north of this area, by Ancholme Head, are 
neither very numerous nor very clear in exhibiting the succession 
of the beds. The lower beds comprise hard grey limestones, 
which Mr. Ussher has grouped with the so-called " Hydraulic 
Limestone" that occurs in parts of Yorkshire in the Lower 
Estuarine Series. These are overlaid by " Semi-oolitic beds," 
forming the main mass of the Lincolnshire Limestone, and on top 
there are " Grey limestones."f 
In North Lincolnshire Mr. Ussher has found it convenient to 
divide the Lincolnshire Limestone as follows : 
FT. 
IN. FT. 
IN. 
Lincolnshire 
f Hibaldstow Beds 
_ 
20 
to 30 

Limestone. 
1 Kirton Beds - 
. 
30 
Oto40 

Basement Beds. 
/ Lower Estuarine Beds - 1 
1 Northampton Sand (Dogger) J 
15 
Oto26 

* Ussher, Geology of Lincoln, p. 54. 
f Geol. Lincoln, pp. 44, 55. 
