342 HEROES OF SCIENCE. 



kinds, some not known in the neighbouring Alps or 

 Apennines, from two to eight feet in diameter. On 

 our ascent to the Superga I saw a thickness of sixty 

 feet regularly stratified of this conglomerate, in 

 which were fragments consisting chiefly of ser- 

 pentine, but some of limestone, others of protogine 

 granite, and one of the latter angular and eight 

 feet in diameter. In less than half an hour's search, 

 I found two of the serpentine and one of the lime- 

 stone pebbles with scratches, which would be called 

 glacial if they were found in a modern moraine, 

 though not such as you would select for examples 

 for a museum. Still I searched this year in some 

 recent moraines quite as long without finding better. 

 As to the age of the beds, there is no doubt of 

 their belonging to the Lower Miocene, the marine 

 fossils of which we collected in strata both below 

 and above them. These enormous blocks, there- 

 fore, were brought into their present position by 

 causes which acted in the Miocene age. I know of 

 no agency but that of ice which could have quietly 

 let them down upon subjacent beds of undisturbed 

 fine marl and sand. Hence I conclude that there 

 was floating ice in the Lower Miocene period, and 

 if the few scratches I saw really imply glacial 

 striation, the ice-rafts were probably derived from 

 glaciers which came down from mountains border- 

 ing the glacial sea ; perhaps from the Alps, for that 

 chain must have existed before the origin of a large 

 part of the Lower Miocene. I have kept the speci- 

 mens I found of these Miocene striated stones to 



