1853.] MORRIS — LINCOLNSHIRE OOLITES. 325 



The strata of this cuttmg, with the exception of the upper portion, 

 are presumed to represent the lowest portion of the white oolitic 

 rocks of the district, or those which immediately overlie the brown or 

 ferruginous rock before noticed, into which the lower sandy bed is 

 considered to pass. These strata offer some peculiar characters in 

 their fossil contents, as compared with other districts, which might lead 

 us to infer a different relative position, and will be hereafter noticed. 



The physical characters of these beds also vary over the district, 

 as might be expected from their nature, so that it is difficult to allo- 

 cate each individual stratum ; but a general uniformity is observable ; 

 the stratified grey sandy clay is seen occurring about the same 

 position in the quarries at Waltham, nine miles south-west of the rail- 

 way. As a general rule, it may be observed that these lower beds 

 have a greater amount of marl in their composition than the upper 

 beds, and this character obtains over a large space : in these beds also 

 is found a certain assemblage of Testacea, some of which also occur 

 in the Inferior Oolite of Gloucestershire. 



The upper portion, or rag beds, are more shelly and pisolitic in 

 structure, sometimes thin-bedded, and frequently showing false bed- 

 ding or oblique lamination ; the inclination of the laminae being about 

 30°, and having in many instances a south-easterly direction. In 

 this series frequently occur thick beds of freestone ; a good section 

 of them is seen in the neighbouring quarries at Houghton Hill. 



Between the Ponton Cuttings are two sections of limited depth, 

 from 6 to 9 feet, consisting of the shelly pisolite with false bedding, 

 and containing many small univalve shells, as Cerithium, NermcBu, 

 Patella (P. ruc/osa), and some small bivalves ; the drift, as noticed 

 at p. 318, covering a portion of one of them. 



The Great Ponton Cutting differs in its general section from that 

 at Little Ponton, in consisting mostly of the upper beds of the series ; 

 at the north end the strata are dislocated and disturbed, having 

 the larger excavations filled with the brown sandy clay, &c., and the 

 smaller ones with rubbly oolite and patches of drift ; about the centre 

 the beds are tolerably uniform in position, and continue with a gradual 

 inclination to the southern end (fig. 1), where they are covered by a 

 thick mass of the northern drift, the inclination appearing greater 

 than it really is, from the rise of the railway line to the same point. 



A slight fault is visible at the northern end, bringing down the 

 shelly beds. The average thickness of the section is about 30 feet, and, 

 about the middle of the cutting, it exhibits, in descending order — 



feet. 



Rubbly oolite • ■ • • • • 5 



Eight to ten beds of shelly oolite, in some parts soft oolite and 

 very fossiliferous, with five zones of Terebratula and Lima 

 in various stages of growth, with intervening shaly beds . 1 5 



A soft marl, containing Oysters in abundance at the north 

 end, dividing and becoming thinner and finely laminated 

 southwards — varying from 1 foot to 4 inches. 



Marly rock, with Corals, NerincBa, Tvrbo ; irregular 2 



Coarse shelly oolites and freestones 15 



