308 



James Durham — Post- Glacial Beds at Dundee. 



J Now it is clear that if the Oarse Clays are laid down on the top 

 of the forest bed, not only had the land stood higher than at present 

 in the first instance, but had been subsequently depressed at least 

 to the level of the top of the Carse Clays, as these are evidently 

 sedimentary deposits in the waters of the Firth, 



It is stated on the most reliable authority that in excavations 

 and well-borings in the Carse of Gowrie the forest bed has been 

 repeatedly penetrated. (See Professor James Geikie's " Prehistoric 

 Europe," pp. 391, 392.) 



In digging the foundation of the new Post Office at Dundee, 

 a section was exposed which seems to throw a valuable light upon 

 the question as to the succession of these beds, for here we have 

 " deposits of the district grouped in chronological order." The 

 situation of this section is about a quarter of a mile back from 

 the natural foreshore of the Firth (docks and similar works extending 

 far out into the estuary) ; between the section and the shore a ridge 

 of rock runs for a considerable distance parallel to the margin 

 of the Firth ; like the post-Glacial beds to the north of it, it is 

 completely covered by buildings, and like them is only exposed 

 during excavations in connection with alterations and rebuilding 

 in this the centre of the most ancient part of the city. 



The level of the street in front of the Post Office is 38 feet above 

 Ordnance-datum. Allowing for the thickness of the blocks and 

 bedding of the street, the top of the section is approximately 35 feet 

 above that base-line, just about the average height of the Carse Clays 

 in the upper part of the Firth. As the total thickness of the beds 

 exposed would be about 25 feet, the bottom of the section would be 

 a little above the present reach of the tide. 



— V COARSE SAND. 



CLAY. 



NEW FOREST BED. 



CLAY. 



FOREST BED. 6-8 INS. 



COARSE GRAVEL. 

 100 FEET TERRACE. 







Section exposed in digging the foundations of the new Post Office, Dundee. 



The excavation revealed the following succession of strata:— ^ 

 At the bottom some five or six feet of coarse gravel, the denuded 

 remains of the 100 feet terrace, then six or eight inches of the far 

 extending forest bed, as usual much compressed ; this is succeeded 

 by 11 feet of clay, above which is 8^ feet of coarse sand. 



I was indebted to the Inspector of Works for the measurements,, 

 so that they may be accepted as absolutely reliable. 



