hunter's posthumous paper on fossils. 335 



the height of 100 to 200 feet, and measured some of them a mile in 

 circumference. Many of them were loaded with beds of earth, and rock 

 of such thickness that the weight was conjectured to be from 50,000 

 to 100,000 tons. Specimens of the rocks were obtained, and among 

 them were granite, gneiss, mica-schist, clay-slate, felspar, and green- 

 stone. They float to the more temperate latitudes, gradually melt, 

 and let drop their mineral ballast to the bottom of the sea. 



Sir James C. Ross, in his antarctic voyage, saw multitudes of icebergs 

 transporting stones and rocks of various sizes, in high southern latitudes. 

 In the voyage of antarctic discovery in 1839, amongst the numerous 

 floating ice-masses, a dark- coloured angular mass of rock was seen im- 

 bedded in an iceberg drifting along in mid-ocean in lat. 61° S. That 

 part of the rock which was visible was about twelve feet in height, and 

 from five to six in 'width, but the dark colour of the surrounding ice 

 indicated that much more of the stone was concealed. This iceberg 

 was between 250 and 300 feet high, and was no less than 1400 miles 

 from any known land. At what distance from its parent cliff that boulder 

 rock was dropped to the sea-bottom is unknown. 



The great boulder-stone in the valley near Derwentwater, will be 

 familiar to all who have visited that beautiful part of the lake district. 

 There is abundant evidence that the whole of that district was formerly 

 covered by the sea. Ancient icebergs then floated over the submerged 

 land of that latitude and longitude, as now over the same latitude, but 

 in a different longitude, which then, perhaps, was dry land. 



The ' boulder-stone,' as it is called par excellence, is one of countless 

 similar but smaller erratics, which by their distribution over the surface 

 of my own native county and the adjoining ones, clearly indicate the 

 course of the currents that bore along the ancient icebergs which dropped 

 them as they floated and melted over that old sea-bottom. 



To appreciate the extent of geological change produced by the annual 

 operation of ice in the form of glaciers and bergs, one must endeavour to 

 multiply the observed approximate results of one year, by the countless 

 thousands of years during which geology teaches that such glacial 

 action has been going on. 



I must not close this brief notice of a geological dynamic, unknown to 

 Hunter, without alluding to the property of ice, especially as blended 

 with earth and forming frozen-soil, in the preservation of animal bodies, 

 and of the evidence which the nature of those animals, as being speci- 

 fically different from any now in being, has yielded of the vast lapse of 

 time during which such soil has been frozen, and the cause of glaciers 

 and icebergs has been in operation, in the latitudes where such frozen 

 animals have been found. To the comparative anatomist these pheno- 



