1871.] 203 [Perry. 



gneiss, as if the former, when in a plastic state, had been moulded 

 upon the latter. Indeed, after careful inspection, one can scarcely 

 fail to note that generally the calcareous bands exactly conform with 

 the most abrupt irregularities and jagged inequalities in the surface 

 of the enclosing walls, and by no means less with the occasional 

 breaks which may be seen in them; that the deposit was everywhere, 

 so made, in consonance with the adjoining rock-masses, as to reveal 

 its more recent origin, in connection perhaps with the action of va- 

 rious mechanical and chemical agencies; and, therefore, that instead 

 of being largely made up of the calcareous remains of Bhizopods, it 

 is not at all of a foraminiferous derivation, but took its place in a 

 vein-like way, the material having been probably either forced up 

 from below in a heated state, or introduced from above in the form 

 of an aqueous solution. 



In confirmation of the view presented, reference ought to be made 

 to the limestones holding " Eozoon " in other localities, and appar- 

 ently belonging to the same part of the series of foliated rocks, as 

 well as to what seem to be kindred calcareous masses subordinate to 

 formations of a very different character. Did time allow, I should also 

 especially like to refer to other limestones, that are probably closely 

 akin, but perhaps of somewhat varying age, limestones which I have 

 repeatedly examined in their several places of occurrence, though 

 they may not be known to hold " Eozoon." Waiving the consideration 

 of these instances, I may, in a word, simply call attention to some of 

 the calcareous masses in Stoneham, because they are intensely interest- 

 ing, as suited both to reveal the processes which have been at work in 

 their own formation and to suggest what has taken place in kindred 

 rocks not so easily known ; for they have a vein-structure, like that 

 of the limestones of Chelmsford and Bolton. This structure, which 

 seems to be common to the several rocks mentioned, is doubtless due 

 to the operation of the same, or of closely allied causes. Portions of 

 these calcareous masses I have found penetrating the adjoining Syen- 

 ite, for with this rock in Stoneham they are more particularly 

 associated, in a vein-like way. This limestone also corresponds 

 exactly with the most ragged and broken surfaces, even with all the 

 most diverse inequalities of the adjacent syenitic rocks. In short, it 

 is so situated in relation to them, as clearly to reveal its more recent 

 origin 



Such are a few of the more important points characteristic of the 



