862 Proceedings of the British Associatmi. 



had obtained crystallized quartz, the blue and green carbonates of 

 copper, chrysocolla, phosphate of copper, arseniate of copper, acicu- 

 lar carbonate of lead, sulphate of lead, sulphuret of iron, white an- 

 timony, and many other minerals. 



Professor Phillips then gave an interesting description oF a bed 

 of magnesian limestone, which exists near Manchester. 



Evening Meeting. 



Mr Murchison exhibited a map of England, coloured to repre- 

 sent some phenomena of physical geography, and for the pur- 

 pose of answering a question proposed by the Association. On 

 a former evening Mr Phillips had given an account of the boulder 

 stones found in the north of England, and which had been traced 

 even as far as Worcestershire. Mr Murchison, in his researches 

 in Wales and the neighbouring counties, had not observed these 

 carried to the country bounded by the Severn, nor had he ob- 

 served any of the silurian gravel carried to the central parts of 

 England. From this he concluded that Siluria must have been 

 formed subsequently to this central part> which might have been 

 an island or part of the continent. In this country of Siluria 

 he had found the deposits of gravel perfectly local ; nor could 

 he perceive in this gravel any recent shells ; on the borders of 

 the South Wales Coal Basin were marks of diluvial action — frag- 

 ments of coal strata being thrown off as from a centre. Another 

 proof of the newer elevation of this part of Britain, are the marks 

 of large lacustrine expanses at recent periods. Out of this tract 

 not only do we observe the boulders of granite extending from 

 north to south, but we find fragments of recent marine shells in the 

 diluvium of Lancashire, Cheshire, Salop, and part of Stafford, all 

 diminishing as we approach the Severn. But he was of opinion 

 that these boulders could not have been so diffused when the sur- 

 face had been dry land, but that the operation must have been ef- 

 fected under the sea, as proved by the presence of these marine 

 shells, and by the fact of boulders having been found on the sum- 

 mits of the sides of valleys, which could not have been brought to 

 those positions save by the agency of currents of the ocean. This 

 later period of the elevation of Siluria, must have produced also the 

 present course of the Severn. In concluding his remarks, Mr Mur- 

 chison mentioned the possibility of icebergs assisting in the trans- 

 port of diluvium. — Mr Conybeare mentioned the fact of chalk 



