62 REPORT—1843. 
Letter from the Astronomer Royal to the Earl of Rossz. Communicated by 
the Ear! of Rossz. 
Birr Castle, 10th August, 1843. 
My pear Lorp,—It is probable that the geological circumstance to which I am 
about to call your attention has already been noticed by the geologists of Ireland; 
but if it has not, perhaps you may consider it sufficiently important to be made the 
subject of a communication to the Geological Section of the meeting shortly to assemble 
under your lordship’s presidency at Cork. 
The circumstance to which I allude is, the existence of numerous traces of glacier- 
friction on the north-west side of Bantry Bay. 
My own examination of that country has been confined to the two lines of road, 
one from Glengariff to Ardagh and into the bosom of Hungry Hill, the other the road 
from Glengariff to the pass leading to Kenmare. Near to both of these roads, marks 
of the glaciers may be seen, but they are more numerous near the former, and espe- 
cially before the road reaches its summit near the Sugar Loaf. The rock is a hard 
and apparently indestructible greenstone slate, and the smallest scratches haye been 
well preserved. Beyond the summit, the rock appears to be clay-slate; and though 
the peculiar swelling form of the surface may still be seen, I do not think that any 
scratches can be found. But in the hollow of Hungry Hill I saw one block (I do 
not remember of what stone) on which the scratches were perfectly preserved. 
I had previously visited the country in the neighbourhood of Scull and Crookhaven, 
and had passed from it to Bantry. Although the rock is sufficiently exposed in this 
tract, and appears to be indestructibly hard, I did not remark any traces of glacier 
action. I have also passed to the north side of the hills dividing Kenmare from 
Glengariff ; but in this tract the rock is not sufficiently exposed to make it probable 
that glacier-traces can be seen. 
I think it right to add, that I have seen the marks of glaciers in the Alpine valleys 
close to the existing glaciers as well as at several miles’ distance from them, and that 
I am perfectly familiar with their appearance. And I have no hesitation in pro- 
nouncing on the certainty of those whose position I have indicated above. 
I am, my dear Lord, your very faithful Servant, 
The Earl of Rosse. G. B. Airy. 
Illustration of the agency of Glaciers in transporting Rocks. 
By Col. Sazine. 
When the Antarctic Expedition had reached 78° S. lat. the vessels were stopped 
by a barrier of ice, from 100 to 180 feet in height, and 300 miles in extent from east 
to west; beyond these cliffs of ice a range of lofty mountains were visible about 60 
miles distant, the westernmost of which appeared to be 12,000 feet in height. From 
the face of these ice-cliffs masses were constantly breaking off and floating north- 
ward, bearing with them fragments of rocks probably derived from the moun- 
tains from which the glacier appeared to descend. In the latitude of 66° and 67°, 
at a distance of 700 miles from the glacier, the ice formed a floating barrrier, through 
which ships could with difficulty force their way. Over the intermediate area the 
icebergs would be constantly strewing masses of rock and detritus, particularly at 
their northern limit, where they would probably form mounds resembling terminal 
glacial moraines. Colonel Sabine then described similar phenomena in Baffin’s Bay, 
which he stated to be, in many parts, deeper than the thousand-fathom line, but 
comparatively shallow at the strait which forms its entrance. The bay was surrounded 
by alternate cliffs of rock and valleys occupied by glaciers, presenting cliffs of ice along 
the shore, from which masses became detached, many of which floated off to the 
zone of shallow water at the entrance of the bay, where they were arrested in their 
progress, and deposited the fragments of granite, trap, and limestone containing 
fossils, derived from different parts around the bay. 

On the cause of the Motion of Glaciers. By Witt1am Hopkins, F.G.S. 
De Saussure had adopted the theory which attributes this motion to the resolved 
part of gravity acting along the inclined surfaces on which all glaciers in motion are 
