April 13, 1900.] 



SCIENC:S. 



575 



beaches, having only two small boat pas- 

 sages leading through the narrow outer 

 land-rims. Both Maraki and Taritari, the 

 the last island of the Gilberts which we ex- 

 amined, are remarkable for the develop- 

 ment of an inner row of islands and sand- 

 bars in certain parts of the lagoon parallel 

 to the outer land-rim, a feature which also 

 exists in many of the Marshall Islands 

 atolls. 



We reached Jaluit the 9th of January, 

 and after a few days spent in coaling, we 

 spent about three weeks in exploring the 

 Marshall Islands, taking in turn the atolls 

 of the Ralick Chain to the north of Jaluit : 

 Ailinglab Lab, ISTamu, Kwajalong, and 

 Rongelab ; and then the atolls of the 

 Eatack Chain, Likieb, Wotje, and Arhno. 

 The atolls of the Marshall Group are noted 

 for their great size and the comparatively 

 small area of the outer land-rims, the land- 

 rims of some of the atolls being reduced to 

 a few insignificant islands and islets. In 

 none of the atolls of the Ellice, Gilbert or 

 Marshall Islands were we able to observe 

 the character of the underljang base which 

 forms the foundations of the land areas of 

 these groups. In this respect these groups 

 are of striking contrast to the Paumotus, 

 the Society Islands, the Cook Group, Niue, 

 the Tongas, and the Fiji Islands where the 

 character of the underlying foundations of 

 the laud-rims is readily ascertained. But, 

 on the other hand, these groups give us the 

 means of studying the m6de of formation 

 of the land-rims in a most satisfactory 

 manner, and nowhere have we been able to 

 study as clearly the results of the various 

 agencies at work in shaping the endless 

 variations produced in the islands and islets 

 of the different atolls by the incessant 

 handling aud rehandling of the material in 

 place, or of the fresh material added from 

 the disintegration of the sea or lagoon faces 

 of the outer land, or of the corals on the 

 outer and inner slopes. It has been very 



interesting to trace the ever-varying condi- 

 tions which have resulted in producing so 

 many variations in the appearance and 

 structure of the islands and islets of the 

 land-rims of the different groups. 



The boring at Funafuti will show us the 

 character and age of the rocks underlying 

 the mass of recent material of which the 

 land-rim, not only of that atoll, but probably 

 also that of the other atolls of the group 

 and of neighboring groups, is composed, 

 though of course we can only judge by 

 analogy of the probability of the character 

 of the underlying base from that of the 

 nearest islands of which it has been ascer- 

 tained. When we come to a group like 

 the Marshalls we have as our guide only 

 the character of the base rock of the islands 

 of the Carolines, which is volcanic, while 

 Nauru and Ocean Islands, to the west of 

 the Gilberts and to the southwest of the 

 Marshalls, indicate a base of ancient ter- 

 tiary limestone. 



Owing to the continued stormy weather 

 and the probability of not being able to 

 laud at these islands while the unfavorable 

 conditions lasted, we did not attempt to 

 visit them. 



After leaving Suva we made a number of 

 soundings from south of N"urakita toward 

 the Marshall Group, which, in addition to 

 those of the ' Penguin,' clearly show that 

 the Ellice Islands are isolated peaks rising 

 from considerable depths (from 1500 to 

 over 2000 fathoms) and that the same is 

 the case with the Gilbert Islands. We 

 made about thirty soundings between the 

 atolls of the Marshalls, which appear to 

 show that they also rise as independent 

 peaks or ridges, with steep slopes, from 

 2000 to 2500 fathoms, and that the so- 

 called parallel chains of atolls of the Mar- 

 shalls, the Ealick and Rataok, are really 

 only the summits of isolated peaks rising 

 but a few feet above the sea-level. The 

 Marshall Islands, as well as the Ellice and 



