THE BUILDING OF AN ISLAND. 



51 



cl, 



in the cliffs beyond Princess, where the writer has X seen bend in the strata re- 

 sembling a large S. The most curious case met with by the present writer, 

 however, is to be seen at Ham's Bluff, where some very thin sheets lying close 

 together in a broader band have been squeezed up into small ripples, the lavers 

 above and below remaining unaffected. This interesting result is shown in the 

 diagram (Fig. 21), and mav be explained by supposing that the waved layers 



Fi( 



2 I. 



Small cnntortioiib in rocks at Hams lilull. 



began to stiffen, for some reason to be sought in their composition, earlier than 

 the adjoining material, so that while the latter yielded to the squeeze the for- 

 mer could only accommodate itself to the reduced space bv falling into folds. 

 It is doubtless the same necessity which has given rise to all contortions, but 

 it is seldom that we meet with so compact and clear an illustration of it. 



Summary. 



To sum up this (luestion of the folding of the " blue-beach " rocks, it will 

 have been seen that in both the Western Oblong and in the Eastern Triangle 

 we possess clear evidence that the ancient strata of the island have been pushed 

 back into folds by some tremendous force acting from about north-northeast, 

 and that the effects of this force have been modified by a force acting crosswise 

 to it. We have been able to mark down approximately the positions of the 

 lines which mark the crests and the hollows of these folds that is to say, the 

 folds that hav^ been produced by the force from north-northeast, and in this 

 way we have come to some idea of how the island's strata are now arranged. 

 The marvel of the removal of the vast masses of the crest of the folds or 

 waves so as to show everywhere the edges of the strata, still remains, a marvel 

 which, after all, is only slightly lessened by our knowledge of the power of the 

 sea and the rains to plane down the land surfaces. 



If we now pause to summarize what we have so far learned about the 

 older of the two formations of our island, we find : 



I. That it is essentiallv different from the younger group, being substan- 

 tiallv a clav formation, while the latter is a lime formation ; the one material a 



