117 



of West Cumberland* and in others, published in various scientific 

 journals. Mr. Kendall has brought forward abundant evidence to 

 convince anyone that the haematite is a substitutional deposit, 

 which has, in some way or another, taken the place of part of the 

 chemically-altered rock adjoining the natural fissures. I would, 

 myself, further, attribute this replacement, not to the infiltration of 

 a ferriferous solution during the deposition of the Red Bocks, but 

 to the complex series of changes initiated by the infiltration of 

 mineral solutions soaking downward through the New Red strata 

 after their deposition. Where permeable strata underlaid the New 

 Red these solutions were diffused throughout a considerable mass 

 of rock, and affected them in few other ways than by staining. 

 But where the downward flow was arrested by meeting with strata 

 impermeable except along certain divisional planes, the solutions 

 were concentrated along those planes, and were kept in contact 

 with the adjoining rock long enough to initiate the important 

 chemical changes that have ended with the replacement of portions 

 of the rock by haematite. That this process of replacement was a 

 very gradual process, and the result of feebly acting causes continued 

 through a long period, is, I think, sufficiently evidenced by the 

 mineralisation of such specimens as that above referred to. Slight 

 as is the difference either in the physical characteristics, or in the 

 chemical composition, between the carbonate of lime of the car- 

 boniferous fossils, and that of the limestone matrix enclosing them, 

 it has been a difference sufficient to determine whether the delicately- 

 adjusted chemical forces should act by removing all the carbonate 

 of lime of the one, leaving the space formerly occupied by the 

 fossil empty ; or whether, concurrently with this, it should, while 

 removing the carbonate of lime of the matrix, replace it atom by 

 atom with other compounds, and end by converting it entirely into 

 solid ore. 



The almost perfect gradation traceable, in the case where the 

 matrix consists of carbonate of lime, from this, through stained, and 

 dolomitized rock into the hematite, may often be traced in hand 



* "Haematite Deposits of West Cumberland." Trans. North of E. Institute 

 of Mining Engineers, vol. xxviii. p. 107. 



