408 PROP. J. PEESTWICH ON THE GLACIAL PERIOD, WITH 



Europe disappeared with the valley-gravels. With the alluvial and 

 peat-beds Neolithic Man appeared, after an unascertained but not 

 necessarily a very long interval, geologically speakiug. In Europe 

 we are unable to carry back his presence beyond a period of from 

 3000 to 4000 years B.C. But already in Egypt, and now in Asia 

 Minor, it is proved that civilized communities and large States 

 nourished before 4000 B.C. Civilized Man must therefore have had 

 a far higher antiquity in those countries, and probably in Southern 

 Asia, than those 4000 or 5000 years ; so that it is possible that the 

 two periods may have overlapped in Europe and in Asia, and that 

 while Man in a more advanced state flourished in the East, he may 

 here in the West have been in one of his later Postglacial stages. 



Discussion. 



The President welcomed Prof. Prestwich back again, and said 

 that he had been greatly missed whilst engaged in other work, for 

 the result of which all were looking anxiously. The paper was 

 calculated to arouse an auimated discussion. Prof. Prestwich had 

 only noticed the geological objections to Dr. Croll's hypothesis. The 

 investigations of the Danish geologists in Greenland afforded valu- 

 able new data. One most important point for consideration was 

 the age of the valley-gravels in England and Northern Erance, 

 which Prof. Prestwich had so ably treated. 



Dr. Evans regretted that he had to differ from the Author, and 

 commented on the boldness of giving numerical estimates of geo- 

 logical time. It was questionable whether the astronomical calcu- 

 lations were quite complete. Considering the deposits formed 

 since the Glacial epoch, both marine and fluviatile, he doubted 

 whether the dates assigned by the Author sufficed. Increased rain- 

 fall might account for some of the denudation, but the amount 

 could not have been immensely excessive or animal life would have 

 suffered more than it did. Marine erosion told a similar story to 

 fluviatile, as in the case of the southern part of what must have 

 been the old valley of the Solent, which must surely have required 

 more than 10,000 or 12,000 years to remove. Still the ordinary 

 views of extent of time might be exaggerated. The speaker could 

 not accept as conclusive the evidence of the preglacial age of man 

 in Wales, and was very doubtful whether the palaeolithic implements 

 found by Mr. Skertchly were in beds of glacial date. Some of the 

 palaeolithic implements in the Eastern districts were made from 

 pebbles brought into the country by glacial action, and it was in- 

 credible that any implements of really preglacial age should be of 

 the same type. Preglacial man might, however, have lived in 

 other parts of the world. 



Dr. Geikie remarked that Sir W. Thomson originally had allowed 

 100 millions of years geological time, and it was on this estimate 

 that Dr. Croll's views were founded. Now, however, Dr. Thomson 

 had limited geological time to about 12,000,000 years. The speaker 



