224; Mr. De la Beclie on ilic lYiffcrences 



in the oolite formation would therefore apj>ear to be as great 

 here as in the Alps, and probably the cause that has effected 

 the one produced the other. 



The dolomite in this range of mountains occurs singularly 

 in the midst of the other beds, like an enormous bed or accu- 

 mulation of beds. As all the strata near it are nearly perpendi- 

 cular, it might even be considered a vein, did not dolomite 

 also occur in the same rocks on the other side of the gulf: 

 the whole country has, however, been violently convulsed ap- 

 parently by serpentine and diallage rock, which sometimes 

 occur beneath and sometimes above the same beds, and some- 

 times may even be seen to cut them. In fact the diallage rock 

 and serpentine of this part of Liguria seem to have acted 

 precisely in the manner of trap rocks, and to have burst up 

 through the stratified formations, after the epoch of the oolite 

 series, and probably after that of a part of the tertiary rocks, 

 for they also are violently disturbed. 



It is hoped that the examples above given, and which might 

 easily be multiplied, of the great mineralogical difierences ob- 

 servable in rocks that would appear to have been formed at 

 the same geological epoch, will be sufficient to show the im- 

 portance of the subject, and induce those not inclined to assent 

 to the theories that have been connected with part of them, at 

 least to examine into the facts ; as by so doing they may disco- 

 ver others, which, either coupled with those before observed, 

 or considered by themselves, may lead to new views, and to 

 the general progress of Geology. We cannot expect that the 

 same rocks should be developed in the same way over the 

 whole surface of our globe; Europe alone proves the con- 

 trary : yet although the parts of a group, like that of the oolite 

 formation, may not be determinable, the whole as a mass may ; 

 and to facilitate the study, rocks in countries distant from 

 each other should first be considered on the large scale, leav- 

 ing the minute divisions (perhaps very useful in one part of 

 the world, but of comparatively little value out of that part,) 

 for examination, till after the existence of the group of which 

 they form a part has been fairly established. It moreover hap- 

 pens, that in countries we may chance to visit, certain rocks 

 may be better developed than in those where the smaller divi- 

 sions have been first established, which Avould thus require very 

 considerable modifications. Besides, rocks may, and do occur 

 in one country and not in another: the muschelkalk is a case 

 in point ; its existence was long denied, — and why ? merely be- 

 cause it had not been observed or was not developed in those 

 countries where its existence was so denied. Now if in one 



part 



