1853.] MORRIS — LINCOLNSHIRE OOLITES. 323 



towards the close of the Drift-clay period and subsequently covered 

 by beds of gravel and loam ; Sir Charles in that case considering the 

 freshwater stream to have been of sufficient force to counteract the 

 causes by the influence of which the boulder-clay was accumulating in 

 the contiguous spaces. The Casewick deposit affords no evidence of 

 a similar nature. 



In estimating the influences which have produced the phsenoraena, 

 a portion of which only are disclosed by the above sections, it will be 

 necessary to consider the general disturbances which have affected 

 the district and the changes it has undergone, viz. the origin of the 

 great transverse valleys, as the Nen, Welland, Witham, and Ouse — 

 the scooping out of the channels and valleys anterior and posterior to 

 the Northern Drift — the overspread of the Drift itself — the dislocation 

 and undermining the oolitic rocks, and their subsequent depression 

 into the adjacent valleys— the re-elevation of land; its effects — the 

 accumulation of freshwater strata — the subsequent covering of the 

 valleys and low grounds by thick gravel deposits ; their partial eleva- 

 tion and denudation, and the final formation of the present vallej^s. 

 These phfienomena are intimately connected vsdth and succeeded each 

 other, producing the physical contour of the present surface, by 

 which the drainage of the district has been permanently effected. 



Part II. The Oolites. 



Between Barkstone and Grantham, including the Peascliff Tunnel, 

 the railway traverses the lower lias, marlstone, and a part of the 

 upper lias, but no detailed descriptions are here given ; the sections 

 exposed afforded the usual mineral and paleeontological characters of 

 the strata, the characteristic species being very abundant in some 

 places. The lower lias at Jericho-wood consisted, in the upper part, 

 of greyish clays passing into dark, slaty, and finely laminated clays, 

 streaked with ferruginous bands and zones of small and large septaria ; 

 the fossils were not distributed throughout, but occurred in bands ; 

 among the most abundant were Ammonites, Belemnites, Pecten, Ino- 

 ceramus, Cardinia. 



■ Commencing south of Grantham, the first or Spittlegate Cutting is 

 through the upper lias, consisting of about 30 feet of dark tenacious 

 clays, with four zones of small and large septaria, generally of a tabular 

 form, and dipping with the clays towards the south-east ; the upper 

 part of the lias is of a grey or light ash colour, resulting probably 

 from atmospheric action ; above this is about 9 feet of very frag- 

 mentary oolitic rock, sometimes ferruginous, and associated with 

 siliceous sand ; some portions were more solid, and appeared as if in 

 situ, but generally the bedding was very irregular and disturbed ; a 

 few fossils only were noticed, chiefly Pectines and SerjmlcB. The 

 lias, however, was tolerably rich in fossils, especially in some places ; 

 among the most abundant were Nucula ovum, Panopcea donaciformis 

 (many in vertical position). Ammonites TVulcottii, A. serpentinus ? 

 The railway crosses the deep and narrow valley of the Witham, which 

 flows over a continuation of the upper lias : in the excavations con- 



VOL. IX. — PART I. z 



