222 Geological Society. 



cite of Wrentham, Cumberland and Mansfield on the borders of the 

 States of Rhode Island and Massachusetts, are of true carboniferous 

 species. The strata containing them, as shown by Hitchcock, Jack- 

 son and others, pass into mica-schist, clay-slate, and other meta- 

 morphic rocks. The bed of plumbago and anthracite, two feet thick, 

 at Worcester, Massachusetts, is separated from the anthracite before 

 mentioned, by a district of gneiss, thirty-five miles wide. This bed 

 Mr. Lyell regards as coal in a still more completely metamorphic 

 state, all the volatile ingredients having been discharged and carbon 

 alone remaining, the accompanying coal-shales and grits having been 

 turned into carbonaceous clay-slate, mica-schist, with granite and 

 quartzite. No similar beds are found in the North American Silu- 

 rian formations. 



May 29. — The Rev. Professor Sedgwick read the conclusion of 

 his " Memoirs on the Geology of North Wales." 



June 12. — The following papers were read : — 



1. " On Fluorine in Bones, its Source and its Application to the 

 ascertainment of Geological Time." By Mr. J. Middleton. 



The author having analysed and determined the amount of fluoride 

 of calcium in recent bone, in that of an ancient Greek, of a mummy, 

 and in the bones of fossil vertebrata from the Siwalic hills, found 

 the proportions increase according to the age. He instituted a se- 

 ries of experiments on aqueous deposits of different kinds and ages, 

 and found fluorine also present in them, with a single exception. 

 He refers its presence in bones to deposition from fluids, and hence 

 accounts for its great abundance in fossil bones, which had long been 

 exposed to aqueous infiltration*. 



2. " On the ChfFs of Northern Drift on the Coast of Norfolk be- 

 tween Weybourne and Happisburgh." By Mr. J. Trimmer. 



The author describes such changes as have occurred along the line 

 of cliffs between Weybourne and Happisburgh since Mr. Lyell's visit 

 in 1840t. He gives an account of the present state of the pinnacle 

 of chalk at Old Hythe point, and holds with Mr. Lyell, that it is 

 separated from the fundamental chalk by the ferruginous breccia of 

 the crag. The southern mass of chalk near Trimmingham has been 

 greatly reduced. The author's observations lead him to conclude 

 that the till and freshwater deposit between Mundesley and Trim- 

 mingham are so interlaced as to indicate that they were in part 

 contemporaneous. He regards the northern drift containing shells 

 as having been transported on ice, but as diff'ering materially from 

 ordinary raised beaches. Mr. Trimmer concludes from the phseno- 

 mena exhibited at Happisburgh, that the land on which the elephant 

 and hippopotamus lived was submerged beneath an icy sea, and that 

 there was an antecedent conversion of a sea-bottom, the Norwich 

 crag, into a terrestrial surface. 



3. A letter was read from Mr. Jeflfreys of Swansea, to the Rev. Dr. 

 Buckland, describing several raised sea-bottoms, forming platforms 

 on the shores of Loch Carron and the neighbouring coast of Scot- 



[* On the subject of this paper see p. 219, supra; also p. 14, 122.] 

 Lt Mr. Lyell's paper was published in Phil. Mag. S. 3. vol. xvi. p. 345,] 



