Wynne — Presidential Address. 305 



Talchir boulder deposits and their distant representatives over the 

 great area referred to. The possibly glacial character of the beds 

 in most cases will leave sufficient matter for contemplation, whether 

 we regard their widely scattered exposures as belonging to one or 

 more than one definite horizon. 



The main conclusions as to the sculptured fragments being 

 really evidence of glaciation, appears to rest prominently upon 

 mere inability to say by what other agency these pebbles can have 

 been striated and facetted or the larger blocks transported. As a 

 rule, they are all foreign to the localities in which they are found, 

 and competent observers have declared they never saw a glaciated 

 pebble presenting similar characteristics. Some have sought to 

 attribute the cutting of their sharp-edged facets to wind and natural 

 sandblast, but this idea has not received support 1 , nor can I contri- 

 bute anything in that direction from observations of my own, 

 though I have been encamped on a sand tract set so actively in 

 almost constant motion by the wind as to convert the castaway 

 empty bottles of one day into ground glass by the next. The 

 sculptured fragments have been compared with a striated pebble 

 from the old red conglomerate of Cumberland, said to have been 

 marked by friction since the rock was consolidated, without this 

 origin for this sculpture being admitted, and neither will the evi- 

 dence of earth tremors, afforded by the worn indentations of the 

 horns of our fossil Irish Elk, suit the case, for even supposing suf- 

 ficient friction of this kind established to produce the results since 

 the fragments became embedded, there is nothing to show how so 

 many as twenty facets, cut at different angles on a single pebble 

 could have been formed in this way, other than by revolving in 

 an icy mass. On the whole, the evidence afforded by these pebbles 

 goes to show that, while the agency of ice a-ffords the nearest 

 approximation to accounting for the features presented, both by 

 themselves and their matrix, differences exist between their strong- 

 est characteristic sand those of the more recent glacial deposits, 

 which have not been yet fully explained. There is also the diffi- 

 culty of bringing widely separated data concerning these boulder 

 deposits into such relation as to afford sufficient grounds for attri- 



1 See a recent Taper upon effects of Sandblast, by E. D. Oldham, Rec. Geol. Surv. 

 Ind., pt. 1, 1889. 



SCIEN. PROC. R.D.S. — VOL. VI. PT. VI. 2 B 



