On the Cambrian Beds of the British Isles. 145 



Triassic age, with which they closely agree in character, but re- 

 marked that the conditions of their occurrence were apparently 

 quite different. 



4. "Analyses of five Bocks from the Charnwood-Eorest District." 

 By E. E. Berry, Esq. Communicated, with Notes, by Prof. T. Gr 

 Bonney, F.E.S., Sec. G.S. 



These analyses are of hornblendic granite from Mount Sorrel, 

 " syenite " from Markfield, Garendon, and Croft Hill, and " porphy- 

 roid " from Sharpley. In the main they confirm the views ex- 

 pressed by Messrs. Hill and Bonney in their communications on the 

 subject, arrived at from microscopic examination, as to the nature 

 and affinities of these rocks. 



January 11, 1882.— E, Etheridge, Esq., F.B.S., President, 

 in the Chair. 



The following communications were read: — 



1. "On the Chalk Masses or Boulders included in the Contorted 

 Drift of Cromer, their Origin and Mode of Transport." By T. 

 Mellard Eeade, Esq., E.G.S. 



The author referred to the occurrence in the Contorted Drift of 

 Cromer of large masses of chalk, and came to the following con- 

 clusions : — The travelled masses are derived from sea-cliffs and the 

 result of landslips, aided by the penetration of water forming ice, 

 intrusive in fissures which detached them from the parent rocks. 

 "Water rising from subterranean sources accumulated as ice around 

 the fallen masses, and was then frozen into the shore-ice. Ice-floes 

 brought into contact with these masses were also frozen into them, 

 forming a raft capable of floating away the boulders. The incline 

 of the shore and the rise and fall of the tides on the breaking-up of 

 the ice would suffice to launch the rafts into the sea ; and they 

 probably floated in water not more than 200 feet deep. The fre- 

 quency of these boulders and their accumulation in the Cromer 

 deposit point to their having been arrested by the shoaling of the 

 water and by stranding on a submarine bank. The nature of the 

 chalk showed that they had not travelled far. 



2. " Observations on the two Types of Cambrian Beds of the 

 British Isles (the Caledonian and Hiberno-Cambrian), and the 

 Conditions under which they were respectively deposited." By 

 Prof. Edward Hull, LL.D., E.K.S., E.G.S. 



In this paper the author pointed out the distinctions in mineral 

 character between the Cambrian beds of the North-west Highlands of 

 Scotland and their assumed representatives in the east of Ireland and 

 in North Wales. In the former case, which included the beds belong- 

 ing to the " Caledonian type," the formation consists of red or purple 

 sandstones and conglomerates ; in the latter, which included the 

 beds belonging to the " Hiberno-Cambrian type," the formation 



