Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 207 



sistent ferruginous stone-bands, 1 probably indicates the final stages 

 of this lateral change. Such changes arc of course among the 

 commonplaces of geology, and parallel examples might be adduced 

 from beds of almost every age at home and abroad. Dr. J. W. 

 Gregory has recently drawn attention to a striking example of 

 similar conditions in the Gault and Lower Greensand of the South- 

 east of England, and he, too, has pleaded the necessity for the 

 recognition of two independent scales, the lithological and the 

 chronological, — 'not contradictory, but complementary, and each 

 must be retained for its special purpose.' 2 



/. The Tealby Clay. 



The available information regarding the exact age of the Tealby 

 Clay along the major part of its course is very meagre, from the lack 

 of clear exposures, and from the perishable character of the fossils 

 which are largely pyritous. 



Most of the sections have already been referred to, and will need 

 very little further description. In the slope above the mine-build- 

 ings near Acre House the clays are exposed in a water-runnel and 

 at a few other places in the same vicinity, including the slip-section 

 already given (p. 203). The fossils noticed here are Belemnites 

 jaculum in tolerable abundance, Exoc/yra sinuata (the large ' Lower 

 Greensand ' form, which is common in the beds C 4 and 5 at Speeton 

 and differs from the allied shell occurring in the zone of Belemnites 

 lateralis), Nucula sp. and several other small bivalves in a poor 

 state of preservation, and some crustacean remains (Meyeria cf. 

 falcifera, Phill.). In this locality the thickness of the Tealby Clay 

 in the mine-shaft is stated at 40 feet. 3 In character it is a rather 

 pale striped blue clay of fine texture, with a few small oval nodules 

 of pale brown exterior and darker interior, which frequently contain 

 fragments of crustaceans. This deposit, in its close lithological 

 correspondence with its equivalent horizon at Speeton, stands alone 

 among the members of the Lincolnshire succession. 



Southward from Nettleton Hill I found no place, where the fauna 

 of the clay could be studied, nearer than the pit at Donnington 

 Station, mentioned on a previous page. The only other fossils 

 which I have found here besides Belemnites jaculum (which is 

 abundant) and Olcostephanus (SimbirsJcites) umbonatus, Lahus., are 

 Eocogyra sinuata (as above), Pecten sp., and other ill-preserved shells, 

 Serpula sp., and Meyeria cf. fahifera (abundant). In the Geol. Surv. 

 ^ILem., Ammonites speetonensis vars. venustus and concinnus 4 , Crioceras 

 Duvalii, and Perna Mulleti are also recorded from this place. 



1 See ' Subdivisions of the Speeton Clay,' Quart. Journ. Geol. Soc. vol. xlv. 

 (1889) p. 594, and sections, figs. 4 & 5. 



' 2 ' On a Collection of Fossils from the Lower Greensand of Great Chart, in 

 Kent,' Geol. Mag. 1895, p. 103. 



3 J. W. Judd, Quart. Journ. Geol. Soc. vol. xxvi. (1870) p. 331. 



4 The specimens under this name are very near to, if not identical with, the 

 form from my Speeton collection figured by Pavlow in ' Argiles de Speeton,' 

 pi. xviii. (xi.) fig. 1, as Olcostephanus (Simbirskifes) Payeri, Toula, a species 

 founded on specimens from the Island of Kuhn, off the coast of Greenland (sea 

 Toula, ' Geologie Ost-Gronlands,' p. 498). 



