1 16 Mr. Weaver on ike Older Stratified 



Devon, and those which have hitherto been met with and de- 

 scribed as constituting the Old Red Sandstone formation. If 

 in attempting to remove this difficulty, namely, as arising from 

 the difference of mineralogical character, we have recourse to 

 metamorpJiism^ what is there gained by sucli an assumption ? 

 We can hardly suppose any very intense development of 

 heat in the present instance. But supposing the highest state 

 of excitement, that of igneous action, could we expect other 

 than an intimate chemical combination of the constituents of 

 the rocky masses, and a new arrangement of the molecules ac- 

 cording to the laws of their polarities? What evidence have 

 we of any such intensity of action in the present case? Not in 

 the mineral characters certainly, nor are the organic remains 

 which are distributed in the series obliterated ; on the con- 

 trar}', they are abundant, and in many cases well pronounced. 

 And the rocks of which the group consists, and to which a ge- 

 neral allusion has already been made, are analogous to such 

 as are to be found dispersed in other transition tracts. Thus, 

 if the Older Stratified Rocks of North Devon be compared 

 with those occurring in certain portions of the South of Ireland, 

 such analogies doubtless present themselves. Inhere are these 

 differences, however, between the two tracts; that a much 

 greater diversity of rocks occurs in the broad expanse of the 

 South of Ireland, than in the confined district of North De- 

 von, including various conglomerates among the number (and 

 in this respect corresponding likewise with the relations in the 

 N.W. of Gloucestershire, and adjacent parts of Hereford- 

 shire*:) while, on the other hand, the organic remains distri- 

 buted in the Old Stratified Rocks of North Devon appear to 

 be much more abundant and in greater variety than I have 

 noticed in any part of the South of Ireland. Now, admitting 

 such analogies to exist, let us carry the comparison somewhat 

 further, and see to what it leads. These rocks in the South 

 of Ireland are overlaid in many instances by detached groups 

 and mountain masses of the Old Red Sandstone formation, in 

 decided unconformed position. The county of Waterford 

 may be cited as affording numerous examples. And in none 

 of these cases do we find anything like a passage from the 

 transition series to the Old Red Sandstone formation above f. 



* See note to §. t34. of my Memoir in the Geological Transactions, 

 vol, i. second series. 



f I have in numberless instances shown that in Ireland the Old Red 

 Sandstone formation reposes on the Older Stratified flocks, both of the 

 transition and primary epochs, in discordant position. Nothing can be more 

 abrupt and distinct than the unconformity of the Old Red Sandstone there 

 displayed. And nowhere have I perceived any gradation between the 

 Old Red Sandstone and the older rocks. (See Geol. Trans., vol. v. Memoir 



