288 Profs. W. King and T. H. Rowney on the 



Its Structural Simulations of Organisms. 



In some other specimens collected at Kynance Cove the sa- 

 ponite encloses calcite on a small scale. It is only by immer- 

 sing the specimens in a weak solution of hydrochloric acid and 

 examining them with a magnifier that they can be seen to con- 

 tain here and there patches and strings of this mineral. The 

 vacant spaces resulting from decalcification are often crowded 

 with projecting configurations of saponite, presenting every 

 variety of form, including regular-shaped aciculae, and no end 

 in shape of arborescences. 



The aciculae, pretty uniform in length and thickness, occa- 

 sionally form a regular layer investing the wall of saponite 

 bounding a piece of calcite ; and they may be in immediate 

 contact, or separated by thin interspaces filled with calcite. 

 In the latter condition they line one side of a fissure in the 

 case represented in fig. 12. In their parallelism, as well as 

 every feature, those aciculae of saponite, it will be seen, differ 

 in nothing except their substance from those which characte- 

 rize the acicular modification of chrysotile occurring in certain 

 ophites, and forming the so-called " nummuline layer of Eozoon 

 canadense" *. 



The arborescences may be simple, or highly complex — large, 

 or small. Fig. 13 represents a medium example — which, it 

 will be observed, closely agrees with typical examples of an- 

 other eozoonal feature, called " canal system," and common 



periods " are not regarded as such ! It is not to be disputed that the crys- 

 talline condition of the primitive rocks has been produced by a crystalli- 

 zation of their mineral components ; but any geologist must be aware that 

 fossiliferous limestones are essentially crystalline through the organic 

 remains they contain having become converted into calcite, and the in- 

 terstitial infiltration of calcareous matter. What any sound geologist 

 will maintain respecting the present condition of undisputed metamorphic 

 rocks is, that it is a superinduced phenomenon, matterless what the tem- 

 perature may have been that developed it; and he will reject as such 

 the limestones just referred to. Carbonate of lime, it is well known, 

 crystallizes with the greatest facility. Oyster-shells, with the animal still 

 living, are often found with their valves consisting of calcite, or Arragonite. 

 So it happens that, besides the fossils in the "limestones" particularized 

 being converted into calcite, the interstices in these rocks contain the same 

 mineral, which, in the form of a calcareous solution, had infiltrated itself 

 into them. But obviously neither the crystallized fossils, nor the calcitic 

 infiltrations, have any analogy with the " pastes, magmas, or muds " from 

 which the Laurentian metamorphics have originated. Sterry Hunt and 

 Giimbel take very little note of what may be assumed as a fact, that the 

 Laurentians have been deeply buried in the earth's crust. Could they in 

 this condition, aided by solutions and a high temperature, remain without 

 undergoing transformation and transmutation ? 



* See ' Annals and Magazine of Natural History/ S. 4. vol. xiv. pi. 19. 

 fig. 4 ; also figures of the same kind in our previous memoirs. 



