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



315 



the bottom of the valley are covered by superficial deposits, which have a united 

 thickness of 22 feet. The upper deposit consists of clay, having interspersed 

 through it small water- worn stones. The nature of the lower deposit has not 

 been ascertained so exactly ; but it is thought, that the upper part of it consists 

 of sand and mud, whilst the under part consists of clay, having interspersed 

 through it angular fragments of sandstone. The following section, drawn to a 

 scale, illustrates the description just given — A represents a very thick bed, or 

 series of beds, consisting of soft red sandstone ; they are here nearly horizontal. 



No. 1 is the upper covering of (boulder ?) clay ; No. 2 is the bed of sand or mud ; 

 No. 3 is the clay with angular fragments of sandstone. The total depth of the 

 excavation is between 80 and 90 feet. It runs in a direction about W.NW. and 

 E.SE., and it has been traced for several hundred yards. 



I have never heard of any organic remains having been found in this lower 

 Boulder-Clay, except on one occasion. I allude to the discovery of an elephant's 

 tusk on the Clifton Hall estate, when the Union Canal was being formed. Mr 

 Bald states that this tusk was found in what he terms the old alluvial cover, 

 and which, from what he says of it, appears to be the same as the deposit now 

 under consideration. The tusk was 39 inches long by 13 in circumference. 



3. The next deposit to be described is the Coarse Gravel, or Stony Clay. 



It is much more sandy and gravelly in its texture than the boulder-clay. It 

 is not nearly so hard, or so difficult to be worked ; and consequently it is not, like 

 the boulder-clay, impervious to water. Its colour is different from that of the 

 former deposit, being not of a black or blue, but of a light brown or straw-colour. 

 There is in this deposit the same absence of laminae as in the former one ; and 

 there is the same want of regular arrangement in the fragments of stone inter- 

 spersed through it. These fragments are neither so large nor so rounded as in 

 the boulder-clay. I have never seen any more than half a ton in weight. The 

 species of rocks from which these fragments are derived are also somewhat diffe- 

 rent. I have seen no mica-slate blocks in it. With this exception, the species 

 of rocks occurring in it, are much the same as in the boulder-clay. 



This gravel or stoney deposit rests generally on the boulder-clay, though 

 sometimes it rests immediately on the subjacent rocks. It may be seen on the 

 new road to Granton Harbour, resting on the boulder-clay. There it is from 10 



