fili Geological Society. 



of the beds 5ri the notth is so like that of the cretaceous series, that 

 were it not for the fossils, they might readily be mistaken ; but to- 

 wards the south a new mineral tyi^e is put on, and the rocks consist 

 of highly calcareous white marl and white limestone. In point of 

 fact, there seems to be as great a chasm between the cretaceous rocks 

 and the tertiaries in America as in Europe. 



A second part of Mr. Lyell's paper gave an account of a series of 

 rocks, called in America the Burr-stone, a siliceous rock, containing 

 fossil sponges, and belonging, it would seem, to the upper division of 

 the eocene period. 



March 12. — A communication was read by Prof. Sedgwick, "On 

 the Comparative Classification of the Fossiliferous Slates of North 

 Wales, with the corresponding deposits of Cumberland, Westmore- 

 land and Lancashire." 



The object of the author in this memoir was to give a general ac- 

 count of the Silurian rocks of the lake district of the North of En- 

 gland, comparing them with those of North Wales, so far as he had 

 hitherto investigated the subject. In both there appears to be a se- 

 ries extending through the various members of the Silurian rocks. 

 In the lake district, the Lower Silurian rocks are imperfectly seen, 

 and are not more than 300 or 400 feet thick, the Ash Gill beds being 

 the highest ; but the Upper Silurians are admirably shown, and con- 

 tain characteristic fossils. Of these latter, the Coniston limestone 

 and the Coniston flags form an important group as much as 1200 of 

 1400 feet thick, and correspond with the Denbigh flags of North 

 Wales and the Wenlock shale and limestone of the Silurian system. 

 The Ireleth slate and grits succeed and occupy a considerable space, 

 and must be of very great thickness. These higher beds in Cumber- 

 land abound with Terebratula Navicula, but above them are remark- 

 able bands with Asterias, while the upper portion is full of fossils, 

 the prevailing type of which is Upper Ludlow. 



April 2. — A paper was read by Mr. Austen, " On an Aerolite 

 said to have fallen near Lymington, Hants." 



A paper was also read by Capt. Bayfield, R.N., "On the Junction 

 of the Transition and Primary Rocks of Canada and Labrador," 



April 16. — A paper was read by Mr. Macintosh, " On the Sup- 

 posed Evidence of the former existence of Glaciers in North Wales." 



Mr. Macintosh combated the opinion of Dr. Buckland as to the 

 origin of scratches and grooves on various rocks, referring these ap- 

 pearances, in many cases, to structural phsenomena. 



April 30. — A paper was read by Mr. Murchison, " On the Palae- 

 ozoic Deposits of Scandinavia and the Baltic provinces of Russia, 

 and their relations to Azoic or more ancient crystalline rocks, with 

 an account of some great features of dislocation and metamorphism 

 along their northern frontiers." 



In this paper Mr. Murchison gave a general outline of the result 

 of his recent examination of Northern Europe, and the conclusions 

 to which he has arrived, chiefly with reference to the classification 

 of a large tract of country before undescribed on a large and compre- 

 hensive scale. 



