580 



DISTRIBUTION OF ORGANIC REMAINS. 



The only effective remedy for the scepticism engendered by such loose comparisons 

 is to publish monographs, with figures of all the remains found in each group of de- 

 posits, the stratigraphical limits of which have been precisely defined by competent ob- 

 servers. This object having been in great measure accomplished in respect to the 

 tertiary and secondary rocks, the inquiry has been recently carried down to the still 

 lower strata of the Carboniferous System. We may, therefore, say that the chrono- 

 logical zoology of the science in England has been, on a general scale, systematically 

 conducted to the verge of the ancient strata illustrated in this work ; though from this 

 step downwards in the series, it must be allowed, that the natural history of the fossils 

 has never yet been directly connected with the order and arrangement of the rocks. 



In the commencement of this volume, while sketching the previous state of our know- 

 ledge of these older formations, I pointed out the confusion which had been introduced 

 by so applying the word " transition " as to embrace in one meaning, the Carboniferous, 

 Old Red, Silurian and Cambrian Systems. If the Old Red Sandstone had been clearly 

 separated from the Carboniferous System above and from the Silurian Rocks below it, 

 the term " transition" (as formerly used by certain English geologists, and applied by 

 them to the lower divisions only) might well have been retained. Seeing, however, 

 that all the continental and most of our native writers had in the mean time extended 

 the application of this word to the carboniferous deposits inclusively, there appeared 

 to be no possibility of preventing confusion without the introduction of a distinct clas- 

 sification. In the previous pages it has I hope been clearly established, that the Old 

 Red Sandstone and Silurian Rocks are completely distinct from the Carboniferous 

 System, by order of superposition and lithological characters ; and my present aim is 

 to prove that they are equally distinct by their imbedded organic remains. 



If this principle of classification, which is established in the arrangement of the ter- 

 tiary and secondary deposits, be once admitted as respects the more ancient rocks of 

 the British Isles, I have no doubt that in other parts of the world, where deposits of 

 the same age occur, it will be found equally true. It is, in fact, only in countries like 

 our own where all those strata exist, which rising from beneath a well- developed car- 

 boniferous system, connect it by unbroken links with the inferior slaty rocks, that such 

 an inference can be sustained ; and hence it follows, that no counter evidence can be 

 received, when derived from tracts in which many of these links are wanting, or where 

 the convulsions and alterations of the rocks have been so great, that the correct identi- 

 fication of their contents is impracticable. Still less can we admit the validity of argu- 

 ments founded, either upon mere lists of fossils which may have often been erroneously 

 identified, or simply upon the names attached to formations by geologists who have 

 not studied the whole sequence of the deposits in question 1 . 



1 On this point I may remark that a paper by Mr. Weaver on the south of Ireland, containing much valuable 

 matter, has just appeared in the Transactions of the Geological Society, vol. iv. This memoir seems to war- 

 rant the necessity of the above caution. After separating the Carboniferous from what he continues to term 



