172 LOWER OOLITIC ROCKS OF ENGLxVND : 
Professor Judd was induced on stratigraphical and palaeontological 
grounds to regard the great calcareous series in that county, 
and also the ferruginous beds below, as belonging undoubtedly 
to the Inferior Oolite.* From 18G7 to 1871 he was actively 
engaged on the Geological Survey in Liutlandahire, and parts of 
Northamptonshire and Lincolnshire, and the results of his detailed 
work fully established the classification that has since been 
generally adopted. 
In describing the main features of the Lincolnshire Limestone 
it will be proper to quote largely from Prof. Judd's Memoir : 
" The beds of the Lincolnshire Oolite display very various 
characters in different localities. Two aspects which it assumes, 
however, may be specially characterised." 
" The first of these we have called the ' coralline facies ' and it 
is characterised by beds of slightly argillaceous limestone, of com- 
pact, sub-crystalline, or but slightly oolitic texture, abounding with 
corals, which are usually converted into masses, of finely crystallized 
carbonate of lime." Tho shells, which by their great abundance 
specially characterize this facies, often occur in the form of casts 
only, and consist of several species of Nerincea, Natica cincta, 
Pholadomya fidicula, and P. Heraulti, Ccromya bajociana, Pinna 
cuneata, Modiola sowerbyana, several species of Lima, and Tere- 
bratula maxillata. " The patches of limestone rock constituted 
in this manner afford ample evidence of having once been coral- 
reefs (see p. 36 ); near Castle By t ham a pit is opened in a rock 
seen to be almost wholly made up of corals." 
" The other variety of the Lincolnshire Oolite, which we have 
called the ' shelly facie?,' consists almost wholly of small shells or 
fragments of shells, sometimes waterworn and at other times en- 
crusted with carbonate of lime. The shells belong to the genera 
Cerithium, Trochus, Monodonta, Turbo, Nerincea, Astarte, Lima, 
Ostrea, Pectcn, Triaonia, Terebratula, Rkynchonella, &c. ; and 
spines and plates of Echinoderms, joints of Pentracrinites, and 
teeth of Fishes also occur abundantly in these strata, which exhibit 
much false-bedding. The Gasteropods are usually waterworn, 
and the specimens of Conchifera and Brachiopoda usually consist 
of single valves often broken and eroded. These beds it is clear 
were originally dead-shell banks, accumulated under the influence 
of constantly varying current?." 
" The rocks of the two facies of the Lincolnshire Oolite do not 
maintain any constant relations with one another ; at some places, 
as Barnack and Weldon, beds of the shelly facies occur almost at 
the base of the series, while at others, as about Geddington and 
Stamford, the strata with the coralline facies occupy that position. 
Sometimes, as at Ketton and Wansford, we find beds in the Lin- 
colnshire Oolite entirely made up of fine oolitic grains, and these 
constitute some of the most valuable freestones. Very rarely the 
grains of which the rock is composed are very coarse, and it 
becomes a pisolite." 
* Geol. Eutland, p. 4. 
