42£ Proceedings of the Royal Physical Society. 



the purpose of Artesian wells, and one for the foundation of a 

 splendid work of art, the new Graving Dock. At a flour-mill 

 situated near the west end of Leith Docks, the section passes 

 through 80 feet of boulder-clay, then through a bed of sand 

 22 feet thick, resting on the solid rocks. The excavation 

 made for the Graving Dock passed through 24 feet of marine 

 sand ; and the boring shows that the boulder-clay is here 35 

 feet thick, when a bed of sand is again reached 18 feet in 

 thickness, or 4 feet less than at the flour-mill section. At the 

 rope-walk on the north side of Leith Links, the boring passes 

 through a bed of marine sand 30 feet thick, then through 70 

 feet of boulder-clay, which at this place is found to rest on 

 the mineralised strata, without any intervening bed of sand. 

 Mr Milne-Home, in his " Memoir on the Lothian Coal-Fields," 

 says, " that at Leith, and in the manufactory lately occupied 

 by a Mr Burstall, a well was sunk through the boulder- clay 

 4.5 feet. A bed of sand and fine gravel was then reached, 

 from which water immediately gushed up, showing that the 

 bed was probably of considerable extent." I am informed that 

 the boring referred to by Mr Milne-Home was made in King 

 Street, a little to the eastward of South Leith Poorhouse ; and 

 the borings since then instituted confirm his remark, and prove 

 that this deposit underlying the boulder-clay is of considerable 

 extent in the neighbourhood of Leith. This lower stratum of 

 sand and shivers possesses a peculiar interest, inasmuch as it 

 seems to imply that a period of time elapsed between the 

 dressings of the rocks and their covering by boulder clay, 

 sufficient to admit of disintegration and the formation of ex- 

 tensive sedimentary deposition. Additional observations on 

 this basement bed of the Taragmite series, and its existence 

 in other localities, are still wanted, and may assist in throwing 

 some light on certain obscure phenomena connected with the 

 formation of the boulder-clay — a deposit which, Dr Fleming 

 remarks, " has been to many pons asinorum " There are 

 numerous examples where the boulder-clay is observed passing 

 upwards into stratified beds of sand and gravel. In the 

 foundation for the new Post-Ofnce of Edinburgh, Mr A. 

 Bryson and myself noticed the upper portion of the boulder- 

 clay becoming of a light-brown colour, with an increased pro- 



