TKANSACTIONS OF SECTION C. 589 



deptlm, in some cases next beneath the soil, in others through a little River Drift 

 (gravel); but in the centrt' of the villa<ire a boriug 218 feet deep has not pierced 

 through the Drift, which reaches to 60 feet below the sea-level. As in a well only 

 60 yards west and slightly higher the (.'halk was touched at G feet there must here 

 be a fall of the chalk-surface of about 12 in 1. Eastward too, on the other side of 

 the valley, the ( 'halk rises to the surface. 



It is noteworthy that in this last case the Geological Survey Map (Sheet 47) 

 shows no Glacial Drift, and rightly so, for in no place does that formation come to 

 the surface, being wholly hidden under narrow spreads of Alluvium and of River 

 Gravel, together only about a quarter of a mile broad at the site of tiie boring. 

 Without the deep well-sections therefore the presence of the Glacial Drift would 

 not have been known. 



The places that have been mentioned range over a distance of 6 miles. How 

 much further the Drift -channel may go we know not, neither can we say to what 

 thickness the slope of the underground chalk-surface may reach ; the slopes given 

 in each case are the lowest possible. 



5. A Criticism of the extreme Glacial Views nf Arjassiz and his Scholars. 

 By Henky H. Howouth. M.F.,'F.S.A. 



In this paper the author rapidly traced the history of the so-called Glacial theory, 

 from the time when ice was first invoked to explain the drift phenomena. 



He discriminated between the earlier phases of the theory, as developed and 

 taught by Oharpentier and Murchison, which explained the facts by postulating a 

 large development of local glaciers in former times, and with whicli he was in 

 complete agreement, and the second phase of the theory, which he described as a 

 glacial nightmare, which was developed by Agassiz and his scholars, and is still 

 generally held and taught, and which appealed to an ice cap or ice sheet covering 

 the polar area and extending far down into temperate latitudes. 



The latter theory had been pressed by Agassiz until he found traces of his ice 

 sheet in the tropics, and even filled the valley of the Amazons with ice. 



Among the followers of Agassiz Dr. Croll has produced the only theory which 

 is current to explain the possibility and nature of such ice caps. He r.rgues for a 

 combined astronomical and meteorological cause, by which each hemisphere has 

 been alternately glaciated and subjected to temperate conditions, and argues that 

 this alternation marked the geological calendar in all time. 



In opposition to Agassiz's theory of an ice cap the author urged : — 



I. The fact that the glacial phenomena only occur over one-half the lands sur- 

 rounding the Nortli Pole, which in this respect may be divided into two semi-circular 

 areas by a line joining the mouth of the Mackenzie river with the eastern shores 

 of the White Sea. They are quite absent in all the district stretching from the 

 Wbite Sea across Asia, over Behring Straits, throughout Ala.ska, and as far as the 

 River Mackenzie. This remarkable fact is fatal to an ice-cap theory, which pre- 

 supposes continuous conditions round the pole. 



II. The evidence of Ilaast. Hector, McOoy, and the other explorers in New 

 Zealand and Australia is unanimous that nothing corivsponding to the drift phe- 

 nomena of the northern hemisphere occurs there, and that there is therefore no 

 evidence of such a condition of things as must have existed in the northern hemi- 

 sphere ; consequently, no evidence of the phenomena upon which an ice cap has 

 been formulated in the.«e latitudes ; but, as the ice-cap theory necessitates a southern 

 glaciation occurring alternately with a northern one, this position again is fatal to 

 the postulate of polar ice sheets. 



III. The unanimous testimony of explorers in the southern hemisphere concurs 

 again, in the conclusion that the great development of glaciers which took place in 

 New Zealand and other places in the southern hemisphere was concurrent and con- 

 temporaneous with the similar development in the northern hemisphere, and did 

 not alternate with it as required by the theory of alternating climates. Upon ihis 

 point Agassiz's views were very pronounced in support of the contention of the 

 author. 



