248 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [-^-pr. 3, 



the pits at Holbeck and Winceby, whence I obtained the following 

 fossils : — Ammonites, several species in the form of casts, Belemnites 

 lateralis, Phil., B. minimus^, Lucina crassa, Sow., and several other 

 bivalves. The most extensive suite of fossils from this part of the 

 formation is from near Bolingbroke, immediately south of which 

 place the beds in question are covered up by the alluvium of the fens. 

 At this place, in addition to the whole of the fossils above men- 

 tioned. Ammonites plieomphalus, Sow., Trochus? (large species), 

 Pholadomya Martini"^, Porbes, Thracia, sp., Pinna (large species), 

 and some other forms, but all in the condition of casts, were found. 

 This is the locality whence were obtained several of the species 

 figured and described by Sowerby in the * Mineral Conchology.' 



The coarse sandstone of this series is the material of which nearly 

 all the churches in this part of Lincolnshire are built ; and its want 

 of durability imparts to many of them, of no great antiquity, a very 

 ruinous and dilapidated appearance. In the railway- cutting at 

 Spilsby large irregular masses of intensely hard greenish-white grit 

 are found, which show no trace of concretionary structure when first 

 dug out, but which, on exposure to the air, soon become soft and of 

 a dark-brown colour, and on being broken exhibit a great number of 

 concentric layers disposed around a central nucleus. 



In many parts of the county, especially about Market Easen, the 

 district occupied by the Lower Sand and Sandstone formed at one 

 time only extensive rabbit-warrens and fir-plantations, some of 

 which still remain ; but in many cases, by the judicious application 

 to this sandy soil of blue clay dug from the beds below, it has been 

 brought into a fit state for cultivation. 



The Lower Sand and Sandstone are throughout Lincolnshire under- 

 lain by hard slaty and shaly beds with numerous compressed Ammo- 

 nites and other fossils. These are highly bituminous and inflam- 

 mable, and have hence been frequently supposed to form a part of 

 the Coal-measures ; they constitute the upper member of that great 

 mass of blue clays which, in this county, represents the whole of 

 the Upper and Middle Jurassic formations. 



V. Paults, &c. 



In the district described in the preceding pages faults, though 

 smaU, are very numerous. The fault at Welton-le-Marsh and the 

 double one at Sutterby have been already mentioned. The small 

 outlier at Gaumer Hill is cut across by several small faults ranging 

 I^. and S., and in that above Ormsby Wood, the beds are inclined at a 

 high angle. In Tetford Hill chalk-pit two faults are seen (fig. 2), each 

 of about 7 feet throw ; and here the workmen have found at diff'erent 

 times open fissures of considerable size : one of these is said to have 

 been "large enough to admit a waggon and horses ; " and it was ex- 

 plored for some distance by the workmen, until fear drove them back, 

 without their having found its termination. In the pit at Nob Hill 

 the beds of the Hunstanton series are seen to be broken up by several 

 small faults; while in that north of Donnington-on-Bain they dip 8°E. 

 In nearly all the pits about Louth small faults occur. In the pit above 



