the Contortions in Palceozoic Strata. 55 



better will it be both for myself and all persons concerned. 

 I assure you that when the thought first struck me I ^was 

 just as much inclined to laugh at it as absurdity as will be 

 the most sceptical of yourselves. It was only after facts had 

 forced themselves upon my notice, time after time, that I 

 mustered up sufficient corn-age to resolve upon my present 

 step. 



I was first led to the conclusion that other than mere 

 local upheavals had determined the dip, strike, and contortion 

 of the palaeozoic strata, by a consideration of the rocks near 

 Melbourne. I find that there, and indeed OA^er the whole 

 colony, the strike is nearly always meridianal, and the con- 

 tortions of such a nature that they could not possibly have 

 been caused by simply upheaving forces ; a lateral pressure 

 seeming to be absolutely required. 



This lateral pressure, so universally demanded to explain 

 geological phenomena, is not accounted for by any theories 

 of cosmical action that I am aware of. Sir Henry De la 

 Beche certainly suggests how it might be originated by the 

 beds of strata becoming oxydized, thus occupying more 

 space than in their pristine condition. He, however, appears 

 to have forgotten that the same deposits must have been 

 already in the form of oxides when first laid down. 



But even this theory of a general expansion of the crust, 

 together with that which supposes the interior of the earth 

 to have contracted as the central heat diminished, fail to 

 account for the singular^ regular, even mathematically 

 straight, direction of the general strike of Australian 

 palaeozoic strata. 



Let us suppose the substance of an artificial globe to shrink 

 independently of the paper covering, or an apple to shrivel 

 in the interior while the rind remained of its original size. 

 Wrinkles would occur in all directions, but such wrinkles 

 would have but little regularity of arrangement, and aught 

 like a parallellism of ridges or of depressions, extending over 

 any wide space, could not possibly be looked for. 



I know of no other theory so well accounting for the 

 phenomenon — supposing it to be by any means general, and 

 with few exceptions it seems, as regards palaeozoic deposits, 

 to be manifested over large tracts of the earth's surface — as 

 an absolute change in the figiire of the earth itself 



That the earth is spheroidal, and not spherical, we know 

 from astronomical observations made with the greatest 

 exactness. We know, too, that the spheroidity is just, or 



