Geology and Magnetism. 513 



These observations are quoted here merely to show the striking 

 coincidence of independent investigations with which the writer 

 was totally unacquainted during his researches in America ; but 

 they clearly prove the universality of the polar lamination. 



During the recent examination of the metalliferous deposits and 

 primary rocks of England and Ireland, we found the old lamination 

 of the United Kingdom, on an average, a few degrees east of north, 

 and the new lamination intersecting it obliquely, in a direction 

 approaching the present magnetic meridian. (See Plate IX.) The 

 same kind of polar structure has been observed in coal beds in all 

 countries. 



The meridional lamination has been observed from Morocco, 

 in the north of Africa, to the most northern parts of Europe ; 

 therefore the crystalline crust of the earth does not consist of 

 confused shapeless masses, resulting from igneous eruptions, but 

 possesses a structure and arrangement of parts as regular and uni- 

 form as any other natural production. It has but one general 

 grain, by which any of the masses will split, and that is from pole 

 to pole, as represented in Plates IV. and V. This meridional grain is 

 produced by the arrangement of the crystals in the granitic base, 

 causing more or less vertical sheets or plates of mica, talc, chlorite, 

 &c, the influence of which, together with the constant circulation of 

 the polar currents in the direction of the planes, extends to the 

 sedimentary beds, and thus the whole of the surface becomes uni- 

 formly cleaved." 



Passing over certain preliminary remarks and criticisms 

 on the prevailing theories of the earth in the sixth chapter 

 entitled * general character of the crystalline rocks, called 

 primary,' Mr. Hopkins offers his own view of the case, which 

 may be termed, a magnetic theory of the earth. 



" We shall consider the ocean as the primary menstruum from 

 pole to pole, — a compound of the elements in solution through 

 which the magnetic currents circulate. From analogy and by ex- 

 periment, crystallization would commence at the negative pole, 

 and would continue to form until its growth would extend to the 

 positive pole in meridional lines, thus producing the polar grain or 



