424 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 
45 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, 
sufiicient 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-Office 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- 
