Vol. 52.] IN YORKSHIRE AND LINCOLNSHIRE. 219 



the fossils which had been done by him and Prof. Pavlow. He 

 thought that the admissions of the Author, however, pointed 

 to the desirability of the use of ammonite-zones in preference 

 to those based on belemnites. He also demurred to the excessive 

 importance attached to minute points of palaeontological evidence 

 when seeming to be in conflict with the stratigraphical evidence. 



Mr. Strahan was prepared to find the palaeontological and strati- 

 graphical grouping of these rocks slightly at variance. He had 

 pointed out some years ago that the Spilsby Sandstone became finer 

 in grain and was partly replaced by clay eastwards. Northwards, 

 towards Speeton, the same change took place, and no doubt the 

 Author was correct in attributing a portion of the clay at Hundleby 

 to that subdivision — on palaeontological grounds. At the same time, 

 it was inexpedient to draw any other line on the map than that 

 which had been taken. The separation of Jurassic from Neocomian 

 in Lincolnshire was based on stratigraphical considerations. A 

 glance at the map showed that the Neocomian group followed the 

 Upper Cretaceous through much of its range across Lincolnshire and 

 Yorkshire ; and though the great overlap took place at the base of the 

 Upper Cretaceous, yet there was also an unconformity at the base of 

 the Neocomian. So far as the North-east of England was con- 

 cerned, no other division between Jurassic and Neocomian than that 

 adopted by the Geological Survey was possible ; had a local name 

 been used in preference to the imported term ' Neocomian,' much 

 confusion would have been avoided. 



He had always regarded the nodule-bed in the Spilsby Sandstone 

 as a true conglomerate — a natural accompaniment of the uncon- 

 formity referred to. The nodules are clustered in a thin band 

 at the base of the rock ; they differ in their mineralization from the 

 indigenous fauna ; the recognizable forms resemble Kimeridge Clay 

 as much as they do Neocomian forms ; the nodules show every 

 degree of wear and tear, and are rounded as though by rolling, and 

 not pitted as they would be by corrosion, nor have they attached to 

 them any of the original shell, nor any adherent organisms. He did 

 not argue that they had been derived from beds now underlying the 

 Spilsby Sandstone, but from strata that had been washed away. 

 The same arguments were applicable to the nodules in the Carstone, 

 which could be readily distinguished into indigenous and derived. 



He thought it a matter for congratulation that they had had laid 

 before them another of the Author's valuable contributions on this 

 interesting group of rocks, and trusted that Mr. Lamplugh would 

 eventually extend his observations to the South Coast. 



Mr. H. B. Woodward remarked that, while in Dorset there was a 

 passage from Kimeridge Clay into Portland Beds, in Lincolnshire 

 the Spilsby Sandstone near Spilsby rested on Upper Kimeridge Clay 

 and north of Caistor it rested on Lower Kimeridge Clay, so that 

 there was a break between the nodule-bed and underlying clays. 

 He said that it should be borne in mind that a similar nodule-bed, 

 also containing derived Portlandian fossils, occurred at the base of 

 <the Woburn Sands at Brickhill, there resting on the Oxford Clay. 



