294 PETEOOEAPHY OF YOEKSHIEE MILLSTONE GEIT. [vol. lxXV- 



were noticeable in the weathered portion of some of the Millstone 

 Grits. 



The Peesident (Mr. Gr. W. Lamplttoh), in closing the Dis- 

 cussion, asked whether the Author's investigations had yet been 

 extended to the sandstones of the Jurassic area in the North Riding 

 of Yorkshire. 



The Atjthoe, after thanking the Fellows for their kind reception 

 of his paper, said that work upon the rocks of the Jurassic System 

 of Yorkshire was just being taken up at Leeds University, and it 

 was proposed to examine, in due course, the Estuarine Sandstones, 

 which offer problems similar to those dealt with in the paper. 

 Answering Dr. Lapworth's question, he said that correlation of the 

 lenticular sandstone and grit-beds of Central and Northern Yorkshire 

 had not been definitely attempted ; but he was convinced of the use 

 of such methods for that purpose, in the same way as had been 

 attempted hj Dr. T. O. Bosworth for the sandstones of Carboni- 

 ferous age in Scotland. Dr. Thomas's statement regarding the 

 widespread distribution of monazite in recent deposits was of great 

 interest, and he hoped that its source would be definitely traced. 

 Pyrrhotite had not so far been discovered in the beds of the 

 Millstone Grit Series, but abundant sulphide of iron occurred in 

 the Coal-Measure Sandstones, and it was quite possible that some 

 of this was pyrrhotite. 



