20y EXPEDITION TO THE 



semen, without bringing together limestones, which in 

 Europe at least, are found of very different ages, unless we 

 adopt the opinion that this oolite is subordinate to the mag- 

 nesian limestone. This we are disposed to do, as we have 

 no reason to believe that the formations of the Mississippi 

 are superior to those of the Wassemon, or that they arc 

 separated by the new red sandstone formation ; if we could 

 venture to express an opinion, where much doubt really 

 exists, we would say that the oolite was of the same age as 

 the asche, or pulverulent limestone, and that it probably 

 constitutes merely an accidental modification of the mag- 

 nesian limestone similar to that observed " at Hartlepool 

 on the coast of Northumberland, where a stratum of hard 

 white oolite exists, the grains composing it being about the 

 size of a mustard seed," and similar to the oolitic varieties 

 which jMr. Freiesleben observed sometimes, though sel- 

 dorn, in the rauchwacke. 



If in the rude and unsatisfactory sketch which we have 

 presented of these formations, we have thrown any light 

 upon a doubtful and obscure point, we doubt not we shall 

 be excused, by the experienced geologist, for the apparent 

 contradictions which we may have revealed. Our object 

 has been to state the facts as they came under our notice, 

 and without any intention to establish a connection be- 

 tween the formations of Europe, and those which we have 

 described. If the facts militate against observations made 

 abroad, we must regret it; but we have only stated them 

 as they have appeared to us. Our opinion remains, how- 

 ever, unchanged, that Whenever these observations shall 

 be repeated under more favourable circumstances, the dif- 

 ficulties will vanish, and the analogy between the forma- 

 tions of Europe and ours, will appear still greater; a due 

 allowance being of course made for those differences whicl« 



