Correspondence — Br. R. D. Roberts. 573 



1872, and afterwards copied into Nature, Sept. 19, 1872, the following 

 passage occurs: — "But a well-boring at Winwick, after penetrating 

 150 feet of Red Sandstone, the upper part of which is placed with 

 the pebble beds in the Geological Survey sheet, was sunk 210 feet 

 through strata consisting of hard rock, stiff red marl, red and 

 white sandstone, with a zone of limestone bands at the base, the 

 boring terminating at 360 feet from the surface, in hard rock." 



In this letter the possibility of finding workable coal under the 

 Trias is fully discussed. I further observed that 1 " was inclined to 

 think" that these beds "belong to the Permian rather than to the 

 Upper Coal-measures." The borings through the Trias at St. Helen's 

 have been made since this letter was written. 



Park Corner, Blundellsajs^ds, T. Mellard Reade. 



Nov. 9th, 1881. 



DR. CALLAWAY'S VIEWS ON ANGLESEY GEOLOGY. 

 Sir, — At page 423 of the September Number of this Magazine, 

 Dr. Callaway states, speaking of the Geology of Anglesey, " that in 

 no case are there any signs of a transition between the altered and 

 unaltered beds." It is not quite clear to what beds he refers as 

 altered or metamorphic beds ; but if he has in view, as I imagine 

 he has, the great gnarled series of Anglesey, which occupies 

 the whole northern part of the island, I venture to take serious 

 exception to his statement. This area of so-called metamorphic 

 rock is represented on the Survey Map as bounded on the 

 south by a great curved fault. On the coast at Forth Corwg, 

 near Point ^lianus, where the fault is represented as running 

 out to sea, a fault undoubtedly does occur, and the gnarled beds 

 are there seen to rest against the shales. As far as I know, 

 this fault is actually seen nowhere else. It has been assumed to 

 exist, as the most plausible explanation of the stratigraphy of the 

 district, and has been so indicated on the map. There are various 

 circumstances which suggest that the line laid down on the map is 

 not the line a great fault would take, and I am in a position to state 

 that no fault occurs at two points (at any rate) of the line indicated ; 

 for a distinct passage can be seen and traced inch by inch from the 

 fossiliferous shales to the beds marked " altered Cambiian " on the 

 Survey Map, and which Prof. Hughes calls the " gnarled series," 

 This passage is shown on the slopes of the north side of Pare's 

 Mountain, where bare rock crops out at the surface for some distance, 

 and the character and texture of the rocks can be distinctly observed. 

 Also at Hafod-onen, near Ehosgoch Station, where, on the bared 

 surface of the farm-yard, the two series can be seen passing into one 

 another, the one dipping under the other. I do not assert that 

 fossilifei'ous Cambrian shales pass into metamorphic rocks, but I do 

 assert that I have seen such shales pass into beds which Dr. Callaway 

 has included under the head metamorphic. If the term metamorphic 

 is used in any strict sense as implying a re-arrangement and crystal- 

 lizing of mineral constituents, I do not see how it can be applied 

 indiscriminately to the " gnarlud series." Parts of the Llandovery 



