280 THE TOABSTONES OP DERBYSHIRE. [Aug. I9°7> 



he regarded the rocks as undoubted ' traps,' and therefore having 

 no connexion whatever with volcanic action. He did not, however, 

 convince Whitehurst, who subsequently printed a second edition of 

 his treatise with the same confident assertion that the toadstones 

 were lavas. So far as the speaker's memory went, it was Jukes who 

 first brought forward evidence that some at least of the toadstones 

 marked contemporaneous eruptions during the time of the Carboni- 

 ferous Limestone, and included interstratified tuffs. The Author, 

 in his first communication, had thrown a flood of fresh light on the 

 volcanic history and petrographical characters of these Derbyshire 

 rocks. His present paper was a worthy continuation of the same 

 careful investigation, and his detailed mapping of the different 

 volcanic areas was an especially-valuable contribution. But, until 

 the stratigraphy of the Carboniferous Limestone has been accurately 

 determined, something must still be wanting for a complete history 

 of the volcanic eruptions of the region. 



Mr. G. Barrow congratulated the Author on the complete 

 account which he had given of the history of volcanic action during 

 Lower Carboniferous times in Derbyshire. That epoch had been 

 marked by volcanic activity in the greater part of the British Isles ; 

 and it was interesting to note that some of the Author's rock-sections 

 showed an identity of structure and composition with specimens 

 from areas so far away as the East Lothians. 



Mr. C. B. Webb rejoiced that the Author had completed the 

 important task which he had undertaken. As want of time had pre- 

 cluded the development of the Author's stratigraphical evidence in his 

 remarks that evening, they were not yet in a position to appreciate 

 the scope of his work. The speaker was glad to hear the Author 

 maintain the existence of sills at Bonsall and Ible, as he had himself 

 for some time suspected that such was the nature of some of the 

 igneous phenomena there exhibited. 



Mr. E. Greenly enquired whether there was any considerable 

 series of basic dykes in connexion with the lavas and sills ; and if 

 so, in what direction was their strike. 



Mr. T. P. Sibly spoke of the valuable assistance which he had 

 received, in his investigation of the faunal succession in the Car- 

 boniferous Limestone of Derbyshire, from the Author's detailed 

 and accurate tracing of the toadstones. 



Mr. G. W. Lampltjgh asked, having regard to the questions which 

 had arisen respecting similar rocks in Ireland, whether the Author 

 had been able to form an opinion as to the time-relation of the 

 intrusive sills and dykes to the contemporaneous volcanic rocks. 



Prof. E. Hull said that he had listened with much interest to 

 the paper, and appreciated the amount of work which had been 

 expended by the Author on his investigations into the volcanic 

 lavas of the Derbyshire limestone. When he (the speaker) was on 

 the Geological Survey, and engaged in levelling sections over the 

 Carboniferous area, he found, on protracting the sections (three in 

 number) to scale, that the Carboniferous Limestone attains a thick- 

 ness of over 3000 feet without reaching the base of the formation, 



