92 Correspondence — Mr. Edward Hull. 



author finds tbe Bargate Beds with pebbles (at Park Hill, Eeigate) 

 separated from the Folkestone Sands only by a thin bed of Fuller's 

 Earth and a layer of sandy chert. The section is now first described ; 

 the dip has been observed and proved, and by measurement this 

 pebble-bed is shown to lie at approximately the same horizon above 

 the Atherfield Clay as when it was last seen west of the Mole. 

 From Reigate eastwards to Tilburstow Hill the same beds are seen 

 in the numerous hollow lanes and pit-sections. The pebble-beds are 

 found approximately on a definite horizon ; but whilst they become 

 of less importance eastward, the overlying cherts, first seen at 

 Eeigate, become of greater importance in that direction. The thin 

 bed of Fuller's Earth, also first seen at Reigate, thickens to the 

 east likewise. 



2. " On the Eastern Limits of the Yorkshire and Derbyshire or 

 Midland Coalfield." ^ By W. S. Gresley, Esq., F.G.S. 



The author attempts to throw light on the question of the 

 easterly extension of the Yorkshire, Derbyshire, and Nottingham- 

 shire coalfield beneath the newer rocks. He notices the general 

 trend of the strata, the sizes of other British coalfields, the question 

 of the origin of mountains, stratigraphical considerations, and the 

 faults of the North of England. His object is rather to suggest 

 what he believes to be novel ways of treating the subject than 

 of reaching conclusions or locating limits. 



3. " On some Phases of the Structure and Peculiarities of the Iron 

 Ores of the Lake Superior Region." By W. S. Gresley, Esq., F.G.S. 



The author has been studying heaps of ore brought from the 

 region lying south-west of Lake Superior since 1890. He describes 

 certain structural features of the ore-fragments, and discusses the 

 evidences of mechanical movements and chemical alteration exhibited 

 by these fragments. 



ooiaiRESiPOiNriDEisrOE. 



THE GEOLOGICAL AGE OF THE EOCKS OF CHAENWOOD FOEEST. 



Sir, — As some uncertainty seems to hang about the origin of the 

 name " Cambrian " as applied to the rocks of Charnwood Forest, 

 will you allow me to make a short statement on the subject. 



Having had occasion recently to refer to the Survey Memoir 

 "On the Geology of the Leicestershire Coalfield," published in 

 1860, for another purpose, I turned to the passage dealing with 

 the Charnwood Forest rocks ; and as regards the origin of the name 

 "Cambrian" as applied to them by the Survey, I thus wrote (p. 11) : 

 " In the absence of organic remains, these rocks have been referred 

 by Professor Sedgwick and Mr. Jukes to the Cambrian period ; 

 amongst other reasons, from their resemblance to the rocks of this 

 age in Wales. They have been described in detail by Mr. Jukes,* 



1 See also a paper on the same subject by Mr. Arnold Lupton, entitled " On the 

 Geology of the West Yorkshire Coalfield" (Trans. Federated Inst. Mining Engineers, 

 vol. vii. pt. 1, p. 137). 



2 Geology of Charnwood Forest, appended to Mr. Porter's History of Charnwood 

 Forest. 



