Yol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 205 



imperfectly-preserved ammonites, very similar to those which 

 occur abundantly in the ' Astarte-bed ' I) 4 at Speeton, were rather 

 plentiful at one horizon in the clay, and also in the ferruginous stone 

 at the base of the pit, the species being the same as at Hundleby. 



Most of the bivalves found in the other pit also occurred here ; 

 and in a silty band in the clay about halfway from the top of the 

 section, along with some small crushed ammonites (Olcostephani), 

 were numerous dwarf univalves and bivalves referable to Dentalium, 

 Cerithium (?), Pecten (a Spilsby Sandstone form), Isocardia (?), 

 Astarte cf. senecta, etc. 



An important feature of both sections is the large admixture of 

 coarse sand with the clay. This occurs throughout in little dabs 

 and streaks, or in thin irregular seams tending to concentrate into 

 shallow cakes of irregular outline, or to be caught up in the con- 

 cretions of iron pyrites. In some places this sand is so coarse as 

 to be almost pebbly, and the quartz-grains have a smooth polished 

 surface, like the grains in the Spilsby Sandstone. Similar sandy clay 

 associated with the Spilsby Sandstone seems to have been met with 

 in the deep boring at Skegness, 11 miles farther east. 1 I have not 

 found this gritty character in anything like the same degree in the 

 Tealby Clay anywhere along its main outcrop under the Chalk 

 escarpment. 



From the Geol. Surv. Mem. (' East Lincolnshire,' pp. 14 and 22) 

 we learn that the ferruginous stratum at the base of the Hundleby 

 pit rests directly upon the Spilsby Sandstone, and that a well was 

 sunk in it to a depth of 14 feet without reaching its base. The 

 rock forming the floor of the Marden Hill pit is mentioned as 

 being ' probably the same bed as that seen at Hundleby ' ; but 

 it appears to me not unlikely that it may represent one of the 

 higher nodular bands of the Hundleby section. The clay at Marden 

 is rather more gritty, while at Hundleby there are bands of ferru- 

 ginous concretions, in the clay above the base of the pit, which are 

 not present at Marden, and the general field-evidence suggests that 

 the Marden section is the higher. 



In the Survey Memoir the Hundleby Ironstone is held to be the 

 southern equivalent of the Claxby Ironstone, and the overlying clay 

 is recognized as forming the base of the Tealby Clay. A list of the 

 fossils of the clay is given (op. cit. p 142), consisting of 13 species, 

 with 9 further cases in which the genus only is determined. It is 

 remarked at the foot of this list that ' this assemblage is also ' 

 (i. e. like that of the underlying Ironstone) ' eminently Neo- 

 comian.' Belemnites lateralis, Ammonites speetonensis and A. Gower- 

 ianus (?) are the cephalopoda mentioned, and these by no means 

 establish the statement, while the remaining fossils, with the ex- 

 ception of one brachiopod, are all lamellibranchs of doubtful value 

 as determinatives in this case. 



At any rate, these sandy clays all fall within the zone of 

 B. lateralis, and, as will presently be shown, their fauna is quite 



1 Geol. Surv. Mem. 1887, ' East Lincolnshire,' p. 169, ; see also Quart. Journ. 

 Geol. Soc. vol. xlix. (1898) p. 472. 



