222 Transactions. — Geology. 



the geology of a sti'ange district euables one to excuse Mr. 

 Reynolds for not being able to see the faces which support 

 that theory; but when he hastily arrives at conclusions 

 about this wonderful formation, and then bases estimates 

 thereon involving the expenditure of thousands of pounds, I 

 cannot help thinking that a little more caution would have 

 been advisable. An eminent geologist from Australia told me 

 he would require at least three months' residence here before 

 he could express any opinion upon the geology of this district. 



The origin of the Boulder Bank is a geological question, 

 and most geologists when dealing with the subject have 

 spoken more or less cautiously, realising the difficulties of 

 the problem. The drift theory from Mackay's Bluff might be 

 the true solution, but there is a good deal of evidence in 

 favour of the other theory, that the Boulder Bank is the 

 upturned edge of a stratum of rock or boulder drift. 



I shall now proceed to give the facts upon which this theory 

 is based, and then mention the difficulties which make it 

 almost impossible to accept the opposite theory. In the hill 

 above the Eocks Eoad may be seen a series of stratified rocks, 

 inclined at very high angles. These rocks incline outwards 

 from the face of the cliff, or, in geological language, they dip 

 easterly. On the beach below the Rocks Road are also rocks 

 standing almost on edge. In some places they have been 

 planed down almost to a dead level by the action of the sea, 

 and are covered by every tide ; but in other parts, where the 

 rocks are harder or less exposed, they are standing up in 

 wall-like ridges above the general level of the beach. These 

 rocks underlie, and are therefore older than those seen in the 

 cliff. This series of rocks may be traced seawards till the 

 Arrow Rock is reached, upon which they evidently lie at a 

 very high angle. Now, it is strikingly apparent that the 

 rocks in the cliff", and also those on the beach, must at one 

 time have extended seawards in the form of an arch, formmg 

 a rounded hill. The Arrow Rock must therefore be regarded 

 as the core of this hill, and this hill was not a mere cone, but 

 had extension northwai'ds and southwards. The strike of the 

 inclined rocks on the beach and in the cliff is north -north- 

 east and south-south-west, and it is also a remarkable fact 

 that the Boulder Bank lies in a similar line. Keeping in 

 mind the fact that a hill once covered the Arrow Rock, that 

 this hill had a northward extension, as is shown by the 

 parallelism of the stratified rocks in that locality, it follows 

 naturally enough that a ridge of hills once occupied the pre- 

 sent site of the Boulder Bank. The core of this ridge is 

 represented by the Arrow Rock, which so far has resisted the 

 denuding action of the sea. This, of course, is deduction, but 

 it is deduction based upon solid facts which cannot be gain- 



