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PROCEEDINGS OF THE GEOLOGICAL. SOCIETY. [May 17, 



ficial boulders, which must m many cases have been brought mto 

 their present situations subsequently to the deposition of the till. 



4. Observations on the Recent Formations in the Vicinity q/^ Edin- 

 burgh. By James Nicol, F.R.S.E., Ass. Sec. Geol. Soc. 



The late discussions relative to the transportal of erratic blocks and 

 the formation of the connected deposits having induced me to believe 

 that the following observations may not be without interest, I now 

 venture to bring them before the Society. They do not pretend to 

 give any general view of the district, which has already been very 

 ably done by Mr. Milne, in a memoir in the Transactions of the 

 Royal Society of Edinburgh, but merely describe a few facts and 

 sections which I have observed at different times. 



The lowest of the recent formations in the immediate neighbour- 

 hood of Edinburgh is the blue or blackish coloured boulder clay, 

 known under the name of the ' Till.' In some other places the till 

 rests on beds of stratified sand seldom more than five or six feet 

 thick ; but in one place, where exposed in a cutting on the Hawick 

 railway, about twelve miles south of Edinburgh, more than ten times 

 that depth. The till is usually regarded as showing no marks of 

 stratification, and hence has been described as originating in some 

 violent and sudden action, unlike any now apparent on the globe. 

 The following sections (figs. 1, 2, 3), which were exposed during the 



Fig. 1. 



formation of the railway from Edmburgh to Leith, show that this view 

 of the nature of the deposits is only partially true, and consequently 

 that the above theory of its mode of origin cannot be maintained. 

 In these sections it will be seen that the blue clay or till contains 

 beds of yellow sand deposited in layers. These beds of sand are very 

 irregular in their extent and in the direction of their lamination. In 

 one section (fig. 2) a portion of the sand is bent over, forming an 

 apparent anticlinal axis. This appearance however I regard as pro- 

 duced during deposition, and not as the result of any subsequent 

 change. In other places the sand forms small nests, or detached 

 masses in the clay, also pro\ang its deposition by local and variable 

 causes, and not by any general rush of waters, w^hich would have 

 mixed up the sand and clay in one confused mass. 



In the clay many boulders occur, from a few ounces to several 



