T. M. Rcade — Compressive Stress in Rocks, etc. 409 



of Christmas Island, and Fernando de Xoronha, in which one 

 could hardly descry any definite remnants of its constituent 

 animals. It had probably' been hurled upon the shore by the 

 frightful wave which at the eruption of Krakatao struck this 

 ooast with such violence and destroyed so many people. I 

 shall as opportunity occurs examine the growth of reef-rock 

 in these seas, but in conclusion I must say that I cannot at all 

 see in Mr. Branner's paper enough evidence to support the 

 theory that these rocks are seolian sandstones, while it appears 

 to me certain that they are nothing more nor less than raised 

 reefs of different ages. 



Note. — Mr. Branner is quite correct in calling attention to the 

 names given to various portions of the island by English and 

 French travellers, which names are quite unknown to the natives. 

 The map published by the Geographical Society from our plan 

 contains most of those really known to the inhabitants. One or 

 two spots which were absolutely unnamed we gave English 

 names to. As to Ilha Rapta as I have called it in this paper in 

 deference to Mr. Branner, all the inhabitants assured us that 

 it w T as Ilha dos Rattos (i. e., Rattos pequenos), but it is likely 

 enough it was originally called Ilha Rapta and the name was 

 altered since. 



Art. XLIX. — The Cause of Active Compressive Stress in 

 Rocks and Recent Rock Flexures / by T. Mellard Reade, 

 C.E., F.G.S., etc. 



I have read with much interest the account of a recent rock 

 flexure on the lower Fox River about six miles northeast of 

 Appleton, Wis., by Mr. Frank Cramer." The rocks appear to 

 have been in a state of stress from lateral pressure beyond any- 

 thing that could possibly be due to gravitation and irregularity 

 of the ground. This stress may have been and probably has 

 been accumulating for a great length of time, the excavation 

 described giving the needed release or in other words acting as 

 the trigger that set off the gun. 



If the effect of the small anticlinal ridge thrown up had not 

 been to crack the walls of the paper mill and dislocate the 

 machinery, the probability is that the movement would have 

 gone unnoticed and it is most likely that such small readjust- 

 ments of the earth's crust take place with greater frequency 

 than is suspected. There is, however, one surface phenomenon 

 which will tend to minimize accumulation of lateral pressure 



* This Journal, March, 1890, pp. 220-225. 



