14 



careous accumulation, this lower limestone, is to be looked upon 

 as I have akeady mentioned to you as being formed in deep 

 water free from muddy sediment, for if there had been a muddy 

 sediment the creatures would not have lived and formed the lime- 

 stone, and we should have got mud limestone instead of calcareous 

 limestone. Consequently there can be no doubt whatever that 

 the area of Clitheroe was the area of deep sea. It must liave 

 been clear sea, removed some distance from the land, for if it 

 were not so we should have got mudbanks or sandbanks. 



Let us pass away from this area of Clitheroe to the area in 

 Derbyshire. There we shall be able to enlarge our ideas with 

 regard to the history of things from the time of the accumulation 

 of these rocks iu Derbyshire. In Derbyshire we have at the very 

 least 5,000 feet in thickness of pure limestone, or limestone nearly 

 pure, implying that for a vast series of ages the deep waters of 

 the ocean rolled over that region. We may therefore take our 

 stand in this district, and we may say that iu Derbyshire and in 

 Clitheroe, and, I would add further, that in all the intervening 

 points, there is proof of the existence of deep sea in the carbon- 

 iferous age. Let us just consider where the line was. Take this 

 to represent a portion of the Welsh hills just at the point where 

 they die away towards the English border into the lower region 

 of the valley of the Dee, or Severn. Eesting upon these older 

 rocks of the Welsh area — Silurian — we have as well-defined a 

 series of petrified beaches representing shingle as ever you saw. 

 The conglomerates would point out that we are close to the mar- 

 gin of the ancient sea. Not only that, but the limestones are 

 thinner, being not more than 1,500 feet iu thickness, and more- 

 over they are associated with sand banks and mud banks, showing 

 beyond doubt that land was ahead. We may take it, therefore, 

 that the condition of the land at that time in that region was 

 very much what it is represented to be on this map. Here you 

 see we have started in Clitheroe, and worked our way into Derby- 

 shire, finding it all deep sea, but when we have gone to the south 

 and west in the direction of Wales we are brought up by land 

 and petrified shingle. Going due south, all along the line from 

 the region where the Severn leaves the area of North Wales 

 proper for a considerable distance there is no limestone. Why 

 is that ? Simply because in those days there was land and not 

 sea, and consequently, there was no chance for limestone to be 

 deposited. The same, too, is the case in the district of Stafford- 

 shire, and with regard to the whole of the area of Charnwood 

 Forest, where, however, we get something like 1,500 feet of lime- 

 stone. So that there is the most clear evidence, from the shingle 

 beaches, the absence of limestones and the presence of sand- 

 stone, and also from plants growing upon the land that the limit 

 of the sea was there. I take it, then, that the line of the sea is 



