554 Revieics — Bryce^s Geology of Arran. 



Dr. Bryce, alluding to these facts, merel}'^ admits that they " tend 

 to sJioio that the granite was injected and elevated after the deposit 

 of the old conglomerate." In the next sentence, advancing a step 

 farther, he adds : " Viewing all these facts in connexion with the 

 general couformability of the Carboniferous strata to the Old Eed 

 Sandstone, and the gradual transition from the one series to the 

 other observed in several places, it is even probable that the injection 

 of the granite took place after the deposit of the Carboniferous 

 formations" (p. 23). But when he goes on to say immediately after- 

 wards, " as the granite of the nucleus is nowhere seen to alter the 

 Carboniferous formations, while it certainly does, as above stated, 

 alter the Old Eed Sandstone, it is quite possible that these Carboni- 

 ferous strata may have been deposited upon the Old Eed Sandstone 

 during a period subsequent to the irruption of the granite," — we know 

 not where to find him. After getting the " probable" and "extremely 

 probable" of the case, why go back to the ''possible," if, indeed, it 

 be a "possible"? 



Summing up at p. 27, "What then, it may be asked, is the con- 

 clusion which we favour, and to be finally drawn from these various 

 and somewhat conflicting statements?" In reply, we have an 

 enumeration, under six particulars, of the " various possible conclu- 

 sions" in the case. For example — 



" 2. The Old Eed Sandstone, and the Carboniferous Sandstones, 

 with their intercalated Limestones and Coal strata, were formed 

 before the granite was exposed to disintegration." 



" 4. If the granite of the nucleus be thus of later age than the 

 Carboniferous strata, then may all the granites be of one age." 



"5. But as the coarse-grained granite cannot with certainty be 

 pronounced newer than the Carboniferous strata, then we may have 

 two ages for these outbursts." 



These are certainly " possible conclusions," — one or other of them 

 is likely to be true ! But which of them the Doctor "favours," or 

 recommends to be " finally drawn," remains undisclosed. 



Nor is Dr. Bryce in any degree clearer or more satisfactory on 

 the other point to which we have referred, namely, the "glacial 

 phenomena" of the island. Speaking of the transported boulders, 

 he says (p. 41) : "We know of only two natural agents capable of 

 producing the effects. These are currents of water and moving 

 masses of ice." But after thus bringing forward two natural agents 

 (allowing this mode of expression to pass as correct) and pronouncing 

 them both "capable of producing the effect," he immediately, in the 

 next sentence, dismisses one of them : "Now the former [i.e. currents 

 of water) are totally inadequate to carry forward masses of the enor- 

 mous magnitude found here, or even to transport the lesser blocks 

 over all the obstacles which they have surmounted in their outward 

 course from the parent rock." Currents of water are thus decisively 

 put out of court. Yet a few pages further on, in describing the 

 Corriegills boulder, he says (p. 74) : " We have already considered 

 the only possible causes [of its transport], and attempted to estimate 

 the evidence in favour of each. That to which we chiefly lean re- 



