TRANSACTIONS OF THE SECTIONS. 103 



the arguments warrant. The fluidity of the interior may be and probably is so im- 

 perfect, that what Mr. Hopkins calls the effective crust, may be sufficiently thick to 

 accord with his deductions, while the actual crust may be comparatively thin. 



The author regarded mathematical reasoning as inadequate to the solution of the 

 question, and pointed out the necessity of relying on more obvious indications. He 

 also showed that the hypothesis of a cavernous structure for the earth's interior is 

 insufficient to account for the great volcanic lines and mountain systems, and con- 

 cluded his paper in the following words : — 



" The argument for the true physical character of the earth admits of a much wider 

 induction of particulars than has generally been imagined. The general facts of 

 geology indicate clearly that all the great masses of land in existence have, from 

 the earliest period of the formation of a crust, been gradually rising with an irregular 

 motion from beneath the level of the sea. Scientific men have been able to observe 

 directly, one instance of this motion in Scandinavia; but every part of the land 

 gives almost equally unequivocal indications of the same truth. Thus South 

 America has evidently been tilted up into a slope, the whole continent having been 

 heaved by a continuous force acting through innumerable ages. The volcanoes at 

 its upper'edge are but the mere outbreaks of its irregular action. And so in every 

 part of the world, where the strata have not been much disturbed and broken by 

 volcanic agency or denudation, we see the history of the land's emergence in the 

 tracings of every successive deposit as it rose above the influence of the ocean. 

 The southern part of our own island is little more than a series of these tracings. 

 We see them in similar order redoubling part of the outline of North America, and 

 we may find similar indications in every part of the world. All these things point 

 to an interior fluid working slowly and solidifying gradually beneath. Let any one 

 observe how any mass of molten matter, heaving from below and gradually hard- 

 ening above, forms to itself a surface broken into angular and uneven pieces at dif- 

 ferent levels ; and then, after taking into account the determination of the ocean 

 currents, and allowing for the effect of other obvious agencies, he will be at no loss 

 to account for the irregularities of the earth's crust, or remain in any doubt as to 

 its real constitution, and the true course of its geological history. Its progress only 

 affords a fresh instance how God can bring about the most varied and beautiful 

 effects and the most beneficial results by the most simple means." 



On the Coal Strata of North Staffordshire, ivith reference, particularly, to 

 their Organic Remains. By R. Garner, F.L.S., and W. Molyneux. 



It is pretty well known that the coal-fields in question repose upon strata of mill- 

 stone grit, and these latter upon the mountain limestone, with its upper beds of 

 shale. From the area of mountain limestone, situated at the east part of North 

 Staffordshire, and constituting the southern extremity of what has been called 

 the back-bone of England, the strata have a general dip westwards ; but this dip 

 is interrupted and the strata elevated along several anticlinal lines, running 

 more or less north and south, and marked by bold ridges or edges of grit ; so that 

 several coal-troughs are formed. A cross section would therefore show the strata 

 to be disposed in a zigzag way. On the surface of the largest coal-field, about 

 50 square miles, the great Potteries have risen, and from its strata 16,000 tons of 

 coal are drawn weekly for manufacturing purposes alone, besides household fuel for 

 100,000 people, as well as coal and ironstone to feed about thirty smelting furnaces. 

 A line of clay-pits, the purple clay of which is very different in quality from the 

 fire-clays of the coal-measures, and which is accompanied by an extremely hard- 

 cemented conglomerate, of a green or yellow colour, marks the south boundary of 

 this principal field. These beds may perhaps be considered to belong to the coal 

 strata, as in the Ordnance sheets ; in some respects they seem as referable to the 

 Permian. At the base of the most westerly ridge the limestone is again attainable, 

 but differing in colour, &c. from that mentioned above on the east side of North 

 Staffordshire ; its fossils are frequently very small specimens of univalves and Belle- 

 rophon. This westerly ridge, constituting* the west limit of the Pottery coal-field, 

 diverges S.W., and the comparatively modern strata of new red sandstone are 

 tilted up by it. It is not the original limit of the coal strata, for these are not only 

 raised conformably to it, but identical beds of coal reoccur on the westerly or. 



