Geological Society. 259 



expression quantity of current occurs here and in many other parts 

 of the book. The student is also informed in a translator's note 

 that a watt is a quantity of energy equal to the product of a volt 

 and a coulomb. On p. 200 we read that " the current which can 

 be obtained from the (secondary) cell, even after short charging, is 

 strong enough to set an alarm-clock in action." Some details 

 ought to be given concerning the internal mechanism of this re- 

 markable clock ; perhaps, however, an electric bell is meant, although 

 even in that case the statement is too indefinite to be of any use. 



The illustrations in the volume are for the most part diagrams, 

 and are well executed. J.L.H. 



XXIV. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 171.] 



May 4th, 1898.— W. Whitaker, B.A., E.R.S., President, 

 in the Chair, 



rPHE following communications were read : — 

 ■*- 1 . * The Carboniferous Limestone of the Country around Llan- 

 dudno.' By G. H. Morton, Esq., E.G.S. 



Llandudno is so well known and frequently visited, that the 

 Carboniferous Limestone and the subdivisions into which it is 

 divided by clear lithoiogical characters may be more easily examined 

 there than at any other similar locality. The subdivisions of ' Lower 

 Brown,' 'Middle White,' and ' Upper Grey ' along the broad belt of 

 limestone from Llanymynech to Prestatyn, and around the Yale of 

 Clwyd, Abergele and Llandulas, have been so frequently described 

 in the Proceedings of the Liverpool Geological Society that it is 

 unnecessary to give any general description of them. At Llandudno 

 the precipitous Great Ormc's Head presents fine sections of the 

 Carboniferous Limestone and the subdivisions referred to, and may 

 be easily examined (with the aid of the appended geological map), 

 in a continuous series of cliffs, ridges, and quarries. The entire 

 succession is, however, not perfect, for the highest beds of the 

 'Upper Grey Limestone' have been denuded, and at the Little 

 Orme's Head the subdivision is altogether absent. 



Copper-lodes on the Great Orme's Head appear to have been 

 worked by the Bomans, and again in recent years until abandoned 

 fully 30 years ago. Some of the lodes are faults, but little can 

 be ascertained about them now, and only two or three are faults 

 with any appreciable amount of dislocation. It is to the undulation 

 of the limestone that the ever-varyin»- dip of the beds is attributed. 

 Numerous fossils occur in the ' Upper Grey Limestone,' and a 

 few are peculiar to the subdivision and the locality, but of these only 

 a single specimen of each has been found. Procluctus margaritactus 

 is abundant, though only an occasional species in other localities, 

 and not found at a lower horizon anywhere else in North Wales. 



