102 REPORT — 1859. 



process there has not heen so long at work ; they want the softness of the further 

 inland hanks. The high-angled banks, too, are terraced with what are commonly 

 called sheep-walks, but which to my mind are incipient landslips — steps in the 

 process of denudation, that process through which the softness, the swelling cha- 

 racter of the interior banks has been attained. Another evidence of the sea's 

 leaving our shores — retiring — is the Limpet (Patellae) markings on the rocks, from 

 where limpets now live, to far above high- water mark. 



The sea then is receding gradually, and the submerged forests are emerging ; 

 they are therefore analogous to the wood deposits known to exist at the mouths of 

 the'large rivers of Europe, Asia, and America. 



A Letter to Sir Charles Lyell on the occurrence of a Land Shell and 

 Reptiles in the South Joggins Coal-field, Nova Scotia. By J. W. 

 Dawson, LL.D., F.G.S. 



[See Journal of the Geological Society of London.] 



On certain Volcanic Rocks in Italy which appear to have been subjected to 

 Metamorphic Action. By Professor Daubeny, M.D., F.R.S., F.G.S. 



Dr. Daubeny called the attention of the Section to two products of volcanic 

 action met with in Italy, the pecularities of which, he thought, had not been fully 

 explained. The first of these is the Piperino rock, met with so extensively about 

 Albano, near Rome, which is distingushed from ordinary tuft" not only by its greater 

 compactness and porphyritic aspect, but likewise by the occurrence in it of nume- 

 rous laminae of mica and crystals of augite, which tend to give it the appearance of 

 a metamorphic rock, or of one which, although originally ejected as tuff, had been 

 subsequently modified by the long-continued action of heat and pressure. The 

 principal difficulty in the way of thus considering it arises from its alternation in 

 several places with ordinary tuff, or with strata of loose scoriae, as is well seen 

 near Marino ; so that it is difficult to conceive how the materials composing the 

 Piperino could have been exposed to heat after their deposition in the form of tuftj 

 without the intervening layers having been subjected to the same operation. The 

 other volcanic product alluded to was the rock called Piperno, foimd near Naples, 

 a brecciated material, in which wavy and nearly parallel streaks of a dark grey, 

 brown, and often almost black colour, occur impacted in a matrix which is for the 

 most part ash-grey, and seems, mineralogicaliy speaking, to resemble trachyte. 

 The imbedded masses occur generally elongated in the same direction, as are also 

 the pores which occur in the midst of the mass. These circumstances have been 

 accounted for by supposing a stream of molten trachyte to have invaded a congeries 

 of fragments of ordinary lava, and to have brought about their partial fusion ; but 

 the Piperno seems to constitute a part of the great tufaceous deposit which over- 

 spreads the neighbourhood of Naples, to which no such metamorphic action is ascri- 

 bable, and that which has been lately met with in the new road now constructing 

 above the suburb of the Chiaja at Naples lies imbedded in the midst of ordinary 

 tuff. Dr. Daubeny therefore conceives that the peculiarities presented by both 

 the rocks alluded to require further elucidation, and that their study might tend 

 to throw some new light upon the effects "of metamorphic action upon rocks in 

 general. 



On the Constitution of the Earth. By the Rev. J. Dingle. 



This paper was intended to be supplementary to one brought before the Associa- 

 tion last year on " The Configuration of the Surface of the Earth." Its object was 

 to obviate some objections to the theory then brought forward, arising from the 

 supposed constitution of the earth's mass. 



Among other objections to the fluidity of the earth's interior which the author 

 endeavoured to controvert, he particularly referred to those which Mr. Hopkins is 

 supposed to have substantiated by mathematical reasoning in his " Researches in 

 Physical Geology," published in the ' Philosophical Transactions ' between 1839 and 

 1842. He observed that these investigations are assumed to have proved more than ' 



