232 Correspondence — C. J. Gilbert. 



C0I?,I?,E!SF01sriDEITCE. 



THE PEEMIAN IN THE MIDLANDS. 



Sir, — Some thirty years ago when I was working in the new Eed 

 Eocks of the Binoingliam district, I found that the Buiiter 

 Conglomerate invariably rested upon a Breccia with a slight 

 unconformity. I pointed this out to the late Mr. Joseph Landon, 

 who also found the same succession at Barr Beacon. Associated 

 with the Breccia were deposits of sandy grit, the formation being of 

 varying thickness. I also found — what was of much greater 

 importance — that there was a very pronounced unconformity between 

 them and the red clays and sandstones upon which they rested. 



On April 12, 1890, I read a paper to the Vesey Club at Sutton 

 Coldfield giving full particulars of this formation, which had never 

 been separately marked on the Survey map, nor mentioned in the 

 Survey memoirs, although its outcrop covered a very considerable 

 area. At that time the red clays which cap the Carboniferous 

 system in this district were mapped as Permian, which accounts for 

 my reference to the breccia beds as a deposit between the " Permian " 

 and the Bunter pebble beds. It is now, I believe, pretty generally 

 recognized that these red clays belong to the Carboniferous system. 

 If this be so, it gives a greatly added interest to these intermediate 

 beds, and it comes to be a question whether they are not really the 

 representatives of the Permian system in this district. 



I was called away from the Midlands shortly after reading my 

 paper, and have since been unable to follow up my investigations. 

 Fortunately, however, this district has been recently re-mapped by 

 the Geological Survey, and I had the pleasure of hearing a paper 

 read by Mr. Cunnington at the Vesey Club in 1914, in which he 

 confirmed ray work and stated that he had found the beds in some 

 places to reach 100 feet in thickness. 



I believe the Survey are proposing to extend their researches, but 

 my chief reason in writing this is to point out that much can be done 

 by local geologists in carrying out a more detailed investigation in 

 regard to these beds. 



A few points I would suggest are : — 



(1) Through how wide an area are they found beneath the Pebble beds ? 



(2) What is their thickness and constitution in different districts ? 



(3) Is the breccia constant in its composition ? 



(4) Are these beds the equivalent of the typical Permian breccias in other 

 places, and are they on the same horizon ? 



(.5) The upper part of the deposit in the Sutton Coldfield district is pure 

 breccia, the grits being beneath the breccia, and the unconformity with the 

 Pebble beds is slight. Is this the rule elsewhere ? 



(6) Can any light be thrown upon the source of the breccia ? 

 And more important than all : — 



(7) Do the grits contain any fossils, and what is their age ? 



In this way much may be done to supplement the work of the 

 Survey, which is naturally of a more general character. 



A splendid section, showing the junction of the Breccia and the 

 Bunter pebble beds can be seen at the Black Pool Quarry at Sutton 

 Coldfield, et the base of which at least a quarter of an acre of the 



