350 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 7, 



mountain-chains I may notice before I conclude, namely the occa- 

 sional dip of the elevated strata towards the central axis of extruded 

 crystalline rock, producing a synclinal, instead of an anticlinal, ridge. 

 Another section copied loosely in the frontispiece to my work on 

 volcanos, from Von Buch's paper on the Tyrol, may show the mode 

 in which I conceive this to have occurred through the injection of a 

 mass of crystalline matter into a wedge-shaped fissure, opening down- 

 wards ; such as must have frequently occurred among the fractures 

 of the overlying strata — giving occasion in some cases to the further 

 rise of the heated and intumescent matter into the hollow between 

 the outer slopes of the synclinal valley. It would indeed accord with 

 the theory suggested above, if such dykes or extravasations at syn- 

 clinal axes were found to alternate frequently with the elevated anti- 

 clinal axes, for the cracks formed in indurated beds of overlying rock 

 would very frequently open alternately upwards and downwards*. 



Time will not allow of my dwelling now upon other points expla- 

 natory of geological problems, which are afforded by the theory of 

 an expansive subterranean crystalline mass preserved by external 

 pressure in a more or less solid condition beneath the crust of the 

 globe, but always ready to expand and perhaps to intumesce upwards 

 on any relaxation occurring in the overlying pressure. But I sug- 

 gest it now, as I did thirty years since, as the solution most recon- 

 cileable with the known facts of the structure and relative position of 

 the great elevated rock-formations of the globe, and as a theory 

 founded, not upon mere guess-work, but on careful and extended ob- 

 servation of the phsenomena of both active and extinct volcanos, and 

 the disposition of volcanic products of all ages. 



May 7, 1856. 

 The following communications were read : — 



1 . On some Footmarks in the Millstone Grit of Tintwistle, 

 Cheshire. By E. W. Binney, Esq., F.G.S. 



Some years since a series of strange impressions was found in one 

 of the lower beds of Millstone Grit in a quarry belonging to James 

 Rhodes, Esq., at Rhodes Wood, near Tintwistle, in Mottram-en- 

 Longdendale, Cheshire. Mr. Rhodes was much struck with the 

 impressions, from the fact of two of them bearing some resemblance 

 to the mark of a human foot ; and the workmen employed in the 

 quarry, when they first showed him the impressions, remarked, 

 *' Master, somebody has been here before us." During several 

 weeks the quarry was visited by many hundreds of people from 

 Glossop and the surrounding neighbourhood. The common opinion 

 was that the impressions were the footprints of some of Noah's 



* See the diagram at p. 205 of ' Volcanos.' 



