224 Mr. R. Mallet on the Origin and Mechanism of 



forced-up columns, let us in one or two instances remark the 

 consequences in which the assumed mechanism must land us. 

 In the case of the 9-inch prism, let us suppose a surface of 

 spheres of 4*1 feet diameter squeezed orthogonally and equally 

 in both directions between the exterior edges and the centre ; or 

 in half a mile there are 640 spheres at the commencement 

 which are squeezed by upward yielding into the same number 

 of hexagonal prisms of 9 inches minor diameter, the aggregate 

 of their diameters in the one line being 640 x '75 feet = 480 feet, 

 deducting which from 2640 feet (half a mile), we find that the 

 centre of figure of the exterior sphere must travel or be forced 

 over the ground upon which they all rest by a distance equal 

 to 2160 feet. 



Is it possible that such an enormous range of transport should 

 ever have occurred in nature and left no trace upon and beneath 

 the base of the basaltic mass ? 



Compressive forces of enormous energy are to be found in 

 nature, but always acting through small ranges. Where have we 

 any examples of such forces acting through such immense 

 ranges as are here required and yet leaving no trace of their ex- 

 istence ? Assuming, however, that such have so acted, the fol- 

 lowing would be amongst the consequences of which evident 

 trace could not but be found : — 



1. The compressive effect in elevating the squeezed-up 

 columns will not be uniform along any one line of spheres, but 

 will be greatest upon those spheres which are nearest to the ex- 

 terior of the surface pressed ; the final effect, therefore, of such 

 compression upon a square mile of spheres 4*1 feet diameter 

 will not be to produce a flat-topped tabular mass of 480 x 2 = 960 

 feet square, but one having the general form of an inverted 

 square pyramid, the prisms being tallest all round the out- 

 side and of least altitude in the centre. Has any such gene- 

 ral form, or any thing even remotely resembling it, in large 

 masses of vertically prismatic basalt ever been observed ? On 

 the contrary, do not all such masses present the general charac- 

 teristic of having nearly level or more or less irregularly convex 

 tops? 



2. If the prisms be produced by the squeezing against each 

 other of a stratum of spheres plastic by heat, then must internal 

 movements have been produced in the mass of each sphere during 

 its distortion, resulting in a distinct molecular structure or ar- 

 rangement of the particles of the prism throughout its length, 

 from which it would result that the prism itself would be more 

 difficultly frangible transverse to its axis (the only direction in 

 which joints are found to occur), and be most easily frangible 

 or cleavable in planes parallel to the sides of the prism, or in 



