300 
disposition of their siliceous spicules, seemed to leave no doubt 
upon this point. A comparison was instituted between the 
coprolites of the Green Sand and those of other formations; in 
the Lower Silurian of Canada, sponge-like coprolites had been 
met with. The chalk flints only differed from coprolites in 
being silicified instead of phosphatised sponges. Ventriculites 
accompanied both, and in both xanthidia and foraminifera were 
found. The phosphate of lime which fossilised the green sand 
sponges might have been derived from the volcanic rocks of 
Lammermuir, and conveyed to them by the cold current which 
afterwards eroded the gault and supplied the silicates to in- 
filtrate the foraminiferal casts. Finally, the formation of 
coprolites appeared to be ae Fae in the Chincha Islands 
at the present day. 
Mr Pary asked how the occurrence of phosphate in Tere- 
bratula was to be explained if the coprolites were to be 
attributed to sponges. 
Mr Sotuas explained that he did not refer all these phos- 
phate nodules to sponges, but to the phosphatization of animal 
matter. : 
Professor LivEineG asked what was meant by the nodules 
being derived from the Gault, for he thought that there 
was no evidence of the nodules occurring in the Gault. 
Mr Bonney stated that nodules corresponding very closely - 
with those of the Upper Green Sand did occur in the Gault, 
as for example in the Barnwell pits and in Roslyn pit at Ely. 
They also occurred high up in the Gault at Folkestone, and 
were not confined to the base of that formation, although layers 
existed there, as at Upware and other localities. He con- 
gratulated Mr Sollas on the excellent work which he had done 
with these obscure organisms, and agreed with his results. 
Mr Patry said that the form of the green grains was too 
regular to make it probable that they were fragments from | 
voleanic rock. 
