OP THE DEVOID COAST-SECTIOlSr. 77 



notably in Thuringia and in the Harz.^ So general is the occur- 

 rence of contemporaneous igneous rocks in the Rothliegendes that 

 Tfaumann long ago divided that formation into the three stages of 

 " anteporphyritic, porphyritic, and post-porphyritic." ^ 



I have only to add that it is a matter of the greatest gratification 

 to me that my assignment of the Breccia Series of Devon to the 

 Permian, for reasons given in this and my former paper, is confirmed 

 by the judgment of so competent an authority as Prof. Hull, after 

 examination of them in the field. 



DlSCTJSSIOlS^. 



Mr. H. B. WooDAVAED remarked that, if the Authors had more 

 fully studied the literature of the subject, their papers (by no means 

 long) would have been considerably curtailed. The chief point of 

 interest was Prof. Hull's opinion on the correlation of the Devon- 

 shire deposits with those of the Midland counties. Coucerning the 

 identification of beds by lithological characters, he observed that the 

 Lower Breccias of Devonshire varied according to the nature of the 

 bordering rocks from which they were derived. In places, too, they 

 included beds of limestone-conglomerate resembling the Dolomitic 

 Conglomerate of the Mendips and the ' Brockram ' of Westmorland. 

 Correlation by lithological characters was the more hazardous, if, as 

 Prof. Hull had stated, there was a great barrier of old rocks sepa- 

 rating the Midland area from that of Devonshire. He asked if there 

 was any positive evidence that the breccias of Shropshire and 

 Worcestershire were Permian? He saw no objection to the lower 

 beds in Devonshire being of Pei^mian age — the subject had been 

 discussed again and again ; but at present there was no actual proof 

 that this was the case, and no fresh facts had been advanced by the 

 xluthors. If their classification of the rocks was correct, then it 

 furnished an additional argument in favour of the view that our 

 Permian and Triassic rocks formed one great Poikilitic Series. 



Mr. HuDLEST0]sr considered that it might be necessary in some 

 cases to recapitulate evidence already adduced in support, for 

 instance, of such a view as the probable Permian age of the 

 breccias at the base of the Eed Rocks. The inference drawn by the 

 Authors from the abundance of contemporary volcanic material 

 seemed a fair one ; and the Devonshire geologists had been accu- 

 mulating a considerable mass of evidence in the same direction, 

 though their interpretation might not be the same. We had been 

 told that the Eed Eockswere one series, and when the speaker first 

 became acquainted with Devonshire geology the whole was regarded 

 as of Keuper age by great authorities. He very much wished that 

 some one would enlighten him as to the grounds for this assumption. 



1 Credner, 'Elemente der Greologie,' 6th ed. (1887) pp. 514-521. 



^ See Appendix to Dr. H. B. Greinitz's ' Zur Dyas in Hessen,' Festschr. des 

 Ver. fiir Naturk. zu Cassel, 1886 ; see also reference to letter from Geinitz in 

 the Author's paper on ' the Permian-Trias Question,' in Geol. Ma^. for 1884, 

 pp. 321 et seq. 



