322 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1917. 



northern limit of the occurrence of Chellean and Acheulian imple- 

 ments in locally postglacial deposits. The " Chelles " fauna is thus 

 evidently younger than the older bowlder clay and older than the 

 younger bowlder clay, and as it is highly developed and of a very 

 temperate facies, it must represent an interglacial period between 

 the older and newer bowlder clays. 



Fourthly, interglacial conditions, according to C. Eeid (06) are 

 shown by the plants in the fossiliferous deposits at Hoxne, Hitchin, 

 Grays, Selsey, Stone, and West Wittering, where beds containing spe- 

 cies which now live only in warmer districts are overlain by deposits 

 of a cold or even arctic climate. 



GLACIATION OF SCOTLAND. 



In Scotland, where the country is more mountainous, the tempera- 

 ture lower and the precipitation heavier than in England, glaciation 

 was proportionately more severe, and we may accordingly expect to 

 find very few traces of any beds earlier than the last general glacia- 

 tion. Those known can be described in small space. A number were 

 mentioned by the late J. Geikie (" Great Ice Age "). 



At Clava, near Inverness, is a fine clay containing marine shells 

 of northern species between two bowlder clays. This bed was in- 

 vestigated by Mr. Fraser in 1882 and Mr. Crosskey in 1886, and each 

 of them considered it to be in situ, and indicating a submergence 

 of over 500 feet, as did the majority of a British association commit- 

 tee which investigated it in 1804 (07). The deposit is 16 feet thick 

 and extends for a distance of at least 100 yards in a well-nigh hori- 

 zontal position. The shells are remarkably well preserved and the 

 deposit is not disturbed or crushed in any way. The fauna is not 

 intensely Arctic but implies colder conditions than the present, ex- 

 cept that many of the Foraminifera are now found only in tropical 

 and temperate and not in Arctic Seas. H. Munthe, a Swedish geolo- 

 gist who visited the section in 1806 (08), considered that, while the 

 organisms from the top and bottom of the section are subarctic, 

 those from the middle are temperate, so that the bed shows a complete 

 climatic wave, but no other geologist has remarked this. It is over- 

 lain and underlain by tough bowlder clay, neither bed being, of the 

 loose moraine type which characterizes the latest glaciations of Scot- 

 land. The similar deposit at Cleongart, Kintyre, was also investi- 

 gated by the British Association committee and by H. Munthe ; here 

 the evidence in favor of the deposit being in situ is still stronger. A 

 fine shelly clay rests directly on coarse gravel with a sharp horizontal 

 junction, and overlain by a dull reddish bowlder clay. The shelly 

 clay has been found in section in the sides of Cleongart Burn and 

 Drumore Burn, about a mile apart, and Tangy Burn, 3 miles farther 



