240 LIAS OF ENGLAND AND WALES : 
Lower beds were exposed in brickyards at Great Gonerby, 
where beneath the floor of septaria, grey shales with bands of 
ferruginous septaria, and a layer with phosphatic nodules, rested 
on dark blue shaly clay with scattered nodules of cement-stone 
and septaria; these beds (beneath the floor of septaria) being 
upwards of 50 feet thick. The dark blue shaly clay has yielded 
the following fossils* : 
Ammonites Engelhardti. 
margaritatus. 
nitescens. 
spinatus. 
Nautilus. 
Belemnites. 
Amberleya. 
Trochus Acis P 
Palseoniso (Trochus) monoplicus. 
Pecten aequivalvis. 
lunularis P 
Goniomya hybrida. 
Gresslya Seebachi. 
Leda graphica. 
Pleuromya costata. 
Unicardium cardioides. 
The outcrop of the band with phosphatic nodules, has been 
represented on the Geological Survey map, at the places where it 
has been seen, from Gonerby northward to Lincoln, as it was the 
only horizon that could be traced. The clays below pass down 
into similar clays with A. c.npricornus, and in the absence of 
sections the boundary of Lower and Middle Lias is naturally 
doubtful. 
Ironstone is again worked at Caythorpe, between Grantham 
and Lincoln, where the following section of the beds was noted 
by Mr. W. H. Daltonf : 
Soil and rubble ... 
f Inferior ironstone 
ni-jji T I Good ironstone 
4 Limestone-band, slightly siliciou 3 - 
(Marlstone). *j Qood irons t one . * . 
[_Sandstone impregnated with iron-ore . 
20 3 
A boring made at this locality, after passing through the iron- 
stone, war, carried to a depth of nearly 300 feet for the most part 
in blue clay (Middle and Lower L ; as). 
Further north the Marlstone degenerates and in places we 
altogether lose the Rock-bed. In Mr. Ussher's opinion the absence 
of the Marlstone between Welbourn and Lincoln is due to a 
horizontal passage into or replacement by clay, the one kind of 
sediment dovetailing into the other. Hard, more or less concre- 
tionary and ferruginous beds represent the last appearance of the 
Marlstone in this area, and they are evidently much like the thin 
beds noticed near Market Harborough. 
Near Wellingore there is a nodular bed with phosphatic 
concretions, and this together with layers of hard grey limestone 
with pyrites, and overlying shales (altogether 12 to 15 feet thick) 
represent the Marlstone, and have yielded the following fossils^ : 
* Jukes- Browne, Geol. S. W. Lincolnshire, p. 36. 
I Geol. S.W. Lincolnshire, p. 40. 
J Ibid., pp. 37, 40-42. 
