222 Reports and Proceedings. 



sulphur present. He did not agree with the author's views as to the cessation of the 

 chemical action by the formation of the bands of hydrated peroxide of iron. The 

 bands, on the contrary, were formed one within the other, and arranged concentrically 

 in the blocks in certain cases, and appeared due to some sort of segregation. 



Professor Ansted justified the application of the name of Sands to these Northamp- 

 tonshire beds. Though many phenomena could not be accounted for by simple 

 mechanical aud chemical action as distinct from what had been termed segregation, 

 he was inclined to accept Mr. Judd's views as regarded these beds. 



Professor Morris considered that the sand was characteristic of only the upper por- 

 tion of this formation, other beds being more oolitic and vesicular in character. The 

 subjacent strata were of an impermeable character ; and this, he thought, had had 

 much to do with the formation of the ironstone beds. Some of the blue ironstones 

 contained as much as 5.5 per cent, of phosphate of iron. There were two varieties, 

 like those of Rosedale, the one magnetic and the other not. In Lincolnshire the 

 marlstone near the surface had been converted into ironstone ; and this fact cor- 

 roborated Mr. Judd's views. 



Professor Maskelyne had observed these sands some years ago near Banbury, and 

 had noticed that many of the hollow nodules of ironstone usually contained a kernel 

 of ochre. Besides carbonic acid, he thought chlorine had played an important part 

 in the formation of the ironstone. In some of the aetites he had mentioned, there was 

 a thin shell of silica. The core in the centre was probably left by the dissolution of 

 the limestone from the interior Some of the disturbance of the rock might be due 

 to expansion from chemical causes. 



Mr. Eoberts remarked that it was quite possible to obtain oxide of iron soluble in 

 water. Perehloride of iron dissolves oxide of iron ; and if this be dialyzed, the 

 crystalloid chloride diffuses away, leaving the oxide of iron in solution. 



Mr. Judd, in reply, remarked that he regarded these beds as having been originally 

 not limestones, but sands, which were converted into ironstones by the deposition of 

 carbonate of iron within them. The name " Sands," if a mineral character was to 

 give the name, was the best term that could be applied to these beds. He had seen 

 nothing in this ironstone for which recognized chemical causes would not account, 

 and he therefore objected to the introduction of unknown agencies to explain them. 

 In nearly all instances the rich dark bands were formed parallel to joint- and 

 bedding- planes. The phosphate of iron might have been removed by solution from 

 certain parts, and the richness in phosphorus of the green ore need not be due to 

 segregation. He thought the beds referred to by Professor Maskelyne were probably 

 the Marlstones rather than the Northampton Sands. He regarded the presence of 

 carbonic acid as certain, while that of chlorine was at the best doubtful, and he 

 therefore was unwilling to call in its agency. 



2. " On the Occurrence of Eemains of Pterygotus and Eurypterus 

 in the Upper Silurian Eocks in Herefordshire." By the Eev. P. B. 

 Brodie, M.A., F.G.S. 



In this paper the author described the occurrence of numerous 

 specimens of Crustacea, chiefly belonging to the genera Eurypterus 

 and Pterygotus in beds of Upper Silurian age, probably the " passage 

 beds," in the Woolhope district and near Ludlow. — Mr. H. Wood- 

 ward said that he had examined the specimens referred to, but he did 

 not think that they presented any new forms. 



n. March 24th, 1869. — Papers read : 1. " On the Cretaceous 

 Strata of England and the North of France, compared with those of 

 the West, South-west, and South of France, and the North of 

 Africa." By Professor Henri Coquand, of Marseilles. Communicated 

 by J. W. Flower. Esq., F.G.S. 



In this paper the author indicated that the agreement between the 

 Cretaceous strata of England and the North of France, as far as the 

 Basin of Paris, is such that the same classification may be applied 

 to the whole, but that, in advancing to the west and south, new beds 

 make their appearance. This is also the case in Algeria, the palse- 



