34 



The mode of growth of the latter was then explained, and 

 specimens of the various plants remarked upon were exhibited 

 by Mr. S. A. Stewart. 



[thied papee.] 



GLACIAL MAEKINGS RECENTLY OBSERVED 

 AROUND BELFAST. 



BY ME. WILLIAM GEAY. 



Geologists have observed a certain superficial accumulation of 

 clay, boulders, gravel, &c, commonly distributed throughout 

 Ireland, England, Scotland, and many other places : it is of 

 various thickness, from one foot to hundreds of feet, and is very 

 irregular in its stratification ; this is called the glacial drift : 

 it is supposed to have been deposited at the close of the Tertiary 

 epoch, and its peculiarities of structure and position are attri- 

 buted to the agency of Ice, either as glaciers or icebergs, passing 

 over the land in one general direction. Commonly too, the con- 

 tained boulders, &c, are scratched and groved to a certain extent, 

 and rubbed smooth : and what is still more remarkable, all the 

 rock surfaces over which the drift occurs are rubbed, polished, 

 and deeply scratched, in the direction of the supposed glacial 

 currents. Mr. Gray exhibited hand-specimens of those marked 

 boulders and rock-surfaces from several localities — from the Car- 

 boniferous Limestone of Castle Espie, County Down ; from the 

 Chalk Cliffs at Ballintoy and Islandmagee ; and from a Trap 

 Dyke in the New Cemetery, on the Falls Road, Belfast. The 

 general direction of the markings is, in all the cases, from the 

 North-East. 



Mr. Gray referred to several instances of the transporting 

 power of the glacial currents ; as, for example, the Chalk of 

 Antrim found in the drift of the County Down, and the Lias 

 Fossils of Islandmagee found in the drift at Castle Espie, and 

 urged that every instance of the kind should be recorded, as it 

 was only by the multiplication of correct observations and re- 

 corded facts we can hope to arrive at sound general conclusions. 



