J. E. Marr — On the Conidon Limesfone. 445 



near Melmerby, do not exhibit their relationships to the nnderlying 

 series, and in the adjoining Lake District there is perfect conformity 

 between the highest member of the Coniston Limestone series (the 

 Ashgill Shales) and the Skelgill Beds, yet the fauna of the Ashgill 

 Shales is not that of the Keisley Limestone, and an analysis of the 

 forms of the latter indicates that it is distinctly on a lower horizon 

 than the Ashgill Shales (which are found in the Cross Fell area in 

 Swindale). 



On p. 296 Mr. Goodchild states that he believes the volcanic rocks 

 of Dufton Pike, etc., are " of pj'roclastic origin everywhere in this 

 area," but he gives no evidence for this belief, which is directly 

 opposed to Mr. Barker's opinion of the nature of these rocks (see his 

 Appendix to our paper on the Cross Fell Inlier), based on careful 

 microscopic examination. 



Mr, Goodchild next notices at some length the geology of the 

 slopes of Eoman Fell, but he only gives the "facts as they appear"^ 

 to him. Professor Nicholson and myself have re-examined the 

 Roman Fell rocks since the reception of Mr. Goodchild's letter 

 containing " the friendly hint." We are willing to admit that our 

 map of the Eoman Fell country is too generalized (though it was 

 distinctly stated that it was a sketch-map for temporary use prior to 

 the publication of the Geological Survey Maps), but we do not see 

 that our general conclusions are thei'eby affected. 



There is probably a cross fault between the Dufton Shales of 

 Hilton Beck (Mr. Goodchild's Helton Beck) and the rocks further 

 south, causing the latter to be shifted back to the east, so that the 

 corona beds should not be taken below the Hilton Shales in the 

 coui-se of the stream. But we cannot recognize any evidence of 

 the intercalation of volcanic beds between two bands containing 

 Trematis corona, for the volcanic rocks on the east side of the Seat 

 seem to us to be distinctly connected with the Skiddaw Slates, 

 and to occur on the east side of the Knock-Flagdaw fault. We 

 did not go over this part of the ground before our paper was 

 written, as our object w^as not a minute description of the sedi- 

 mentary and volcanic rocks of the Skiddaw Slate Series. Whilst, 

 therefore, I see no objection to the intercalation of volcanic rocks 

 in the Corona beds (it is well known that they are intercalated on 

 more than one horizon between different sedimentary bands of the 

 Sleddale group), I am not convinced that such occurs on Eoman Fell, 

 though we have recently re-examined the ground for this special 

 purpose.' When Mr. Goodchild remarks, however, " I more than 

 suspect that these Helton Moor volcanic rocks are the equivalents in 

 time of those I named the Eake Brow Series," which he has else- 

 where identified with the volcanic rocks of Eycott Hill, we look 



1 Mr. Goodchild appears to have misunderstood Prof. Lapworth's information 

 about the Corona beds, for Prof. Lapwovth tells me he knows of no corona beds at 

 Girvan, or elsewhere in Scotland. Perhaps Mr. Goodchild refers to the occurrence 

 of two bands of Trematis in the Shropshire area, which Prof Lapworth tells me he 

 has found there. In quoting so eminent an authority as Prof. Lapworth in support 

 of a controversial point, surely we are justified in expecting that a correct version of 

 Prof. Lapworth's statement should be given. 



