316 



PKOCEEDIKGS OF THE GEOLOGICAL SOCIETY. [May 22, 





Table 



[continued). 





No. of 

 bed. 



Lithology. 



Organic remains. 



Thickness. 







Brought forward .... 



ft. in. 

 14 4i 



6 



Black fissile shale 



A. contorta &c. 



2 



5 



Second bone-bed, loose in 

 texture. 



Coprolites &c. 



Oi 



4 



Loose grey micaceous sand- 



Bones, teeth, scales, and 



4 





stone, highly fossilife- 



coprolites, spines of Hy- 







rous. 



bodus and Nemacanthus, 

 casts of M. minima, Pul- 

 lastra arenicola, &c. 





3 



Bone-bed imbedded in a 



Coprolites, worn bones, 



1 





pyritoLis matrix 



small pebbles, scales, and 

 spines, portion of jaw 

 of Lepidotus {GiebeW^), 

 teeth of Hyhodus minor, 

 H. plicatilis, Sargodon 

 tomicus, Gyrolepis Al- 

 berti, Acrodus minimus, 

 Saurichthys apicalis, Ter- 

 matosaurus Alberti, and 

 Ichthyosaurus. 





2 



Black fissile shale with thin 



A. contorta, S. cloacinus, co- 



8 





veins of grey pyritous 



prolites, &c. 







stone. 







1 



Loose grey micaceous sand- 



A. contorta, portion of jaw 



1 





stone. 



of Pliosaurus ?, bones, 

 teeth, and coprolites. 





r.) 



Blue marl of the Keuper. 







25 10 



The first traces of this Ehaetic tract, for it can boast of only a very 

 limited surface- area, occur a little beyond the third bridge, about a 

 mile and a quarter from the new station at the south end of the 

 town of Gainsborough, where the lowest bed of the series, 'No. 1 in 

 the section, is seen resting unconformably, though with parallel 

 stratification, on the biue marl of the Keuper beneath. This bed 

 consists of a rather loose micaceous sandstone of a greenish grey 

 colour, containing a few specimens of Avicula contorta, with worn 

 bones, teeth, and coprolites, and is (where not affected by the un- 

 evenness of the underlying Triassic marl, the hollows of which it 

 fills up) on the average about a foot in thickness. In one part, near 

 the outcrop of this lowest bed, lying directly on the blue marl be- 

 neath, I found part of the right ramus of the lower jaw of a large 

 Saurian, probably that of Pliosaurus. This sandy bed, as a com- 

 mencement of the Ehaetic series, does not seem to be elsewhere of 

 usual occurrence, — the lowest stratum below the bone-bed, in most 

 other localities, being the weU-known black shale, of a character 

 more or less indurated, which at Garden Clifi", Wainlode, Coombe 

 Hill, Penarth, and elsewhere, as described by Dr. Wright in vol. xvi. 



