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



would necessarily produce a deposit of a totally different character ; and more- 

 over, they could not have been spread over the district except by a body of 

 water, much more tranquil than that which existed dm-ing the deposition of the 

 boulder-clay. The nature of the materials forming the deposit beneath the 

 boulder-clay, and the manner in which they have been deposited, equally attest 

 the comparative tranquillity of the waters at that period, — the period which im- 

 mediately succeeded the elevation and dislocation of the stratified rocks. On the 

 other hand, it is most manifest that, at the period when the boulder-clay was 

 deposited, the waters were in a state of violent and extensive commotion. It is 

 just what might be expected to result from a cataclysm, which washed over a 

 country and bared it of its soil to an enormous extent ; — and this idea is a good 

 deal strengthened, by the fact of an elephant's tusk having been found in the 

 boulder-clay. For this discovery shews, that when the boulder-clay was depo- 

 sited, a country inhabited by animals existed to the westward, the soil of which 

 was therefore such, as to support a luxuriant vegetation. It is true that no ve- 

 getable remains have as yet been noticed in this boulder-clay ; but, considering 

 the extraordinary resistance which attended the transport and deposition of this 

 clay, it is not likely that many vegetables would be preserved in it, or indeed that 

 there should be even any animal remains in it, except such as were of the hardest 

 materials. 



3. After the epoch of the boulder-clay, the waters which then covered this 

 district, appear not to have been agitated by any currents of an extraordinary de- 

 scription. The deposit which lies above the boulder-clay, contains no blocks of 

 stone that required great force of water to transport them. On the contrary, 

 they are comparatively small and angular in their shape, and may all have been 

 derived from the neighbouring district. But that there were currents in the 

 water at this time is proved, (1.) by there being such a deposit ; and, (2.) by 

 the subjacent boulder-clay having been in some places entirely washed away. 

 The materials thus abraded from the boulder and stony clay, may have supphed, 

 in part at least, the beds of clay and sand, which form the deposit next in order. 



4. When we examine the character and contents of these sandy and argilla- 

 ceous deposits, we see proofs of much greater tranquillity in the waters, than would 

 have existed during the immediately preceding period. The accumulations of 

 clay and sand which prevail over considerable portions of the district, shew that 

 the submarine currents had greatly lessened in force. I have mentioned, that 

 the pieces of rock found in this particular deposit are generally very small, and 

 that the beds of clay and of sand are usually laminated. This is a state of things 

 which clearly justifies the above inference. 



At this period, it would appear that the level of the waters had probably 

 fallen below what it had previously been, for the sand and clay which marks the 

 epoch now referred to, is not found at a higher level than 700 feet above the pre- 



