66 Dr Buckland's Address. 



tween tliem and recent species. The fossil shells of this formation, which - 

 the author calls the Norwich Crag, are partly marine, and partly fresh- 

 water, and indicate a fluvio-marine origin, and the proportion of living 

 species was found to be between 50 and 60 per cent. This deposit, 

 therefore, the author refers to the older pliocene period. A similar exa- 

 mination was then made of 230 species of shells from the red crag in Mr 

 Wood's museum, and it was found that 69 agreed with living species, be- 

 ing in the proportion of about 30 per cent. This group, therefore, Mr 

 Lyell ascribes to the miocene era. A collection of 345 species of coral- 

 line crag shells in Mr Wood's cabinet was then compared in like manner, 

 and 67 were determined to be identical with recent species, being about 

 19 per cent. Mr Lycll, therefore, considers that the coralline crag is also 

 miocene, although belonging to a more remote part of that period than 

 the red crag. Having obtained from M. Dujardin a collection of 240 

 shells from the Faluns of Touraine, he found, with Mr George Sowerby's 

 assistance, that the recent shells were in the proportion of 26 per cent., 

 so that he has now come round to the opinion long ago announced by 

 M. Desnoyers, that upon the whole the crag of Suffolk corresponds in age 

 with the Faluns of Touraine, both being miocene, although the species 

 in the two countries are almost entirely distinct, those of England having 

 a northern, and those of France a sub-tropical character. I am also in- 

 formed by Mr Lyell, that out of 400 marine and fresh-water species, from 

 the eocene strata of the London and Hampshire basins, Mr George 

 Sowerby was scarcely able to identify two per cent, with living shells. 

 It is satisfactory, therefore, to observe that the test of age, derived from 

 the relative approach to the recent fauna, is in perfect accordance with 

 the independent evidence drawn from superposition. We ascertain, for 

 example, by superposition, that the fresh-water strata of the mud cliffs of 

 East Norfolk rest on Norwich Crag, and are the newest formation of all. 

 They are then followed in the descending series by 1st, the Norwich ; 

 2dly, the red; and, 3dly, the coralline crag, beneath which is the Lon- 

 don clay. The same order of sequence is indicated by the organic re- 

 mains considered independent!} - , and simply with reference to the degree 

 of their correspondence with the existing fauna. 



It has been known for many years, that near Bridlington, in Yorkshire, 

 sand and clay containing marine tertiary shells had been exposed on the 

 coast. From an examination of the shells collected there by Mr Bean. 

 Mr Lyell finds the deposit to agree in age with Norwich Crag. 



I cannot conclude these remarks without observing, that some part of 

 the confusion and apparent inconsistency of the opinions of different con- 

 chologists, respecting the age of the crag, must have arisen from the in- 

 termixture of fossils derived equally from the Norfolk and Suffolk beds, 

 or from strata, some of which now turn out to be referable to the older 

 pliocene, others to the miocene period. 



From an examination of some fossil shells, identical with recent species 

 collected by Capt. Bayfield from the most modern deposit near the Gulf 



