THE AGE OF SOME EXISTING SPECIES OF PLANTS, 815 
dwellings in Switzerland, for which I am indebted to J. T. Lee, 
Esq., F.G.S., are fai . My colleague Mr. W. Faweett 
has recently brought me from America grains of maize from the 
Without an intelligent observer and recorder the be no 
definite determination of time. We can only speculate as to the 
period required for effecting the changes represented by the various 
deposits 
an unknown antiquity. They are subsequent to the last changes 
in the surface of the country, and represent the physical conditions 
still prevailin 
examination of these beds has, however, been made by Mr. vid 
Robertson, F.L.§., who has thoroughly investigated the contents 
of the strata explored in the excavation of the Dry Dock, Garvel 
ark, Greenock. It is evident that these beds record an earlier 
Phase of life than the beds at Crofthead. The arctic sh lls ar 
associated with the plant-bearing beds, and the plants themselves, 
while consisting to a large extent of ‘‘ agrarian species, Ineine 
i The remains of flowering 
