148 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Search for "Atlantis" with the Microscope.* — Under this 

 Leading Dr. A. Geikie reviews a paper f by the Abbe Eenard " On the 

 Petrology of St. Paul's Kocks," au island nearly on the equator, and 

 about 500 miles east of the South American coast ; — 



" Are these rocks the last enduring remnant of ' Atlantis ' — a 

 continent that has otherwise disappeared, or are they portions of a 

 volcanic mass like the other islands of the same ocean ? To those 

 who have not noted the modern progress of geological inquiry, it may 

 seem incredible that any one should propose to solve this problem with 

 the INlicroscope. To seek for a supposed lost continent with the help 

 of a Microscope may seem to be as sane a proceeding as to attempt to 

 revive an extinct Ichihjosaurus with a box of lucifer-matches. Yet in 

 truth the answer to the question whether the St. Paul's Eocks are 

 portions of a once more extensive land depends upon the ascertained 

 origin of the materials of these rocks, and this origin can only be pro- 

 perly inferred from the detailed structure of the materials, as revealed 

 by the Microscope. The importance of microscopical examination in 

 geological research, so urgently pressed upon the notice of geologists 

 for some years past, has sometimes been spoken of disparagingly, as 

 if the conclusions to which it led were uncertain, and hardly worth 

 the labour of arriving at them. We occasionally hear taunts levelled 

 at the ' waistcoat-pocket geologists,' who carry home little chips of 

 rock, slice them, look at them with their Microscopes, and straightway 

 reveal to their admiring friends the true structure and history of a 

 whole mountain-range or region. That the sarcasm is often well- 

 deserved must be frankly conceded. Some observers with the Micro- 

 scope have been so captivated with their new toy as to persuade 

 themselves that with its aid they may dispense with the old-fashioned 

 methods of observation in the field. But there could not be a more 

 fatal mistake. The fundamental questions of geological structure 

 must be determined on the ground. The Microscope becomes an in- 

 valuable help in widening and correcting the insight so obtained ; 

 but its verdict is sometimes as ambiguous as that of any oracle. In 

 any case it must remain the servant, not the master, of the field- 

 geologist." 



M. Eenard has undertaken a most elaborate investigation (chemi- 

 cally and microscopically) of sections of the rocks brought home by 

 the ' Challenger,' with the view of determining whether they were to 

 be considered as volcanic or to be classed among the crystalline 

 schists. If they belong to the latter, they must once have lain deeply 

 buried beneath overlying masses, by the removal of which they have 

 been revealed. They would thus go far to prove the former existence 

 of much higher and more extensive land in that region of the Atlantic ; 

 land, too, not formed of mere volcanic protrusions, but built up of 

 solid rock-masses, such as compose the framework of the continents. 

 If, on the other hand, the rock is volcanic, then the islets of St. Paul 

 belong to the same order as the oceanic islands all over the globe. 

 The Abbe inclines on the whole to the side of the crystalline schists, 



* Nature, xxvii. (1882) pp. 25-6. t Ann. Soc. Belg. Micr., ix. (1882). 



