310 MR MILNE ON THE MID-LOTHIAN AND EAST-LOTHIAN COAL-FIELDS. 



This deposit of clay has interspersed through it, in most places, an immense 

 quantity of stones. They vary in size, from small gravel to blocks many tons in 

 weight. These stones seldom lie precisely in contact ; — they are often separated 

 b}^ intervals of several feet. They do not pi-esent any regularity of position in 

 the clay ; — and are not even collected in heaps. The heaviest are not always at 

 or near the bottom, nor are the lightest always at or near the top : — the lightest 

 and heaviest occupy indiscriminately all parts of the bed. 



The blocks of stone found in this clay are most usually roimd-shaped, and 

 perfectly smooth in then' smface. There are, however, two remarkable exceptions 

 to this rule in this district, which are worth mentioning. In widening the road be- 

 tween PiershiU barracks and Portobello a few years ago, the Road Trustees came 

 upon an enonnous mass of trap; — the lower part of it, was imbedded in the boulder- 

 clay, the upper part in sand. The mass was sharp and jagged in its outline, as if it 

 had not been transported far. It was quaiTied for road metal, and about ten cart- 

 loads, or nine tons of stones, were got from it. Another block of the same de- 

 scription was found on Craigentinny farm, near FiUieside, which yielded so much 

 as fifty cart-loads of stones. These masses were stated to have been a dark- 

 coloured whin. 



These are the only two cases I know, where the fragments of rock imbedded 

 in this deposit of clay were not found rounded and smooth. I should add, how- 

 ever, that, at Cowpits and some other places, I have seen a layer of angular frag- 

 ments at the bottom of the deposit ; — this was, where the clay Avas incumbent 

 on, and in contact with, the stratified rocks. The fragments Avere most generally 

 sandstone, and appeared to have been derived from the strata immediately sub- 

 jacent. 



Among the rounded blocks, I have found (near the shore of the Firth of 

 Forth), Basalt, Granite, Mica-slate,* coarse compact Conglomerate, coarse Sand- 

 stone, Quartz-rock, Limestone, compact Felspar of a deep red colour, besides 

 ten or twelve varieties of greenstone. Though these boulders are generally 

 smooth, some of them have ruts or scratches on their upper sides, and which 

 have been apparently produced by the passage over them of harder bodies. I 

 have more particularly observed these ruts or scratches on blocks of limestone, 

 sandstone, and greenstone. It is an object of some importance to ascertain the 

 direction of these ruts, — but it is at very few places in the district where this 

 can be ascertained. The direction of the ruts can be very distinctly seen, along 

 the shore at Joppa near Portobello, and at Seaficld near Leith. They appear at 

 both places to range between W. and W.SW. by compass, but the most general 



• In a bye-road which runs to the east of North Leith church, there was, iu 1 837, a block of mica- 

 slate about 4 feet in diameter. The author of a useful little work, entitled " Excursions illustrative of 

 the Geology and Natural History of the neighbourhood of Edinburgh," 1 835, states, that he found a 

 block of mica-slate with garnets in it two miles south of Dalkeith, (p. 70.) 



