177 
of differential resolvents, and to the detection of such 
properties as are common to these forms. The field is fruitful 
of results. 
Mr. R. D. Darbishire read a Paper “ On Marine Shells 
in Stratified Drift at High Levels on Moel Tryfaen, Caernar- 
vonshire.” 
After recapitulating shortly the development of the present 
theories of alteration oflevel and glaciation in the Caernarvon- 
shire district, and especially referring to the discovery, in 
1881, of marine shells in drift-beds near the top of Moel 
Tryfaen by the late Mr. Joshua Trimmer, F.G.S., Mr. Darbi- 
shire described his rediscovery of the fossiliferous deposit in 
extensive sand cuttings made during the present year in 
opening out the Alexandra Slate Quarry on the north side of 
the hill. 
Professor Ramsay had traced marine drift to the height of 
2,300 feet above the level of the sea in the recesses of Carnedd 
Dafydd and Carnedd Llewellyn, and had found fragments of 
shells near Maenbras, two miles west of Snowdon, at about 
the same height as Mr. Trimmer had given ; but other- 
wise the discovery of 1831 had scarcely been followed up, 
nor even had any complete list of Mr. Trimmer’s shells been 
published. 
By repeated barometric observations, Mr. Darbishire had 
ascertained the fossiliferous beds to extend upwards from 
1,380 to 1,360 feet above tire sea level, confirming Mr. 
Trimmer’s own measurement. 
Last week, the section being about 35 feet in vertical 
height, exposed on one line the following series : 
UNDER THE SWARD. 
Black peaty soil. 
FT. IN. 
0 9 
1 9 
1 9 
Yellowish brown sandy clay, finely and No shells or 
tortuously stratified with scattered, j- fragments 
rounded, and angular pebbles ! observed. 
Fine sandy gravel, stratified Ditto. 
