152 NATURAL SCIENCE [September 



best to repair the deficiency by a bold appeal to " the possibilities 

 of creation." The result is " frightfully thrilling." We give a few 

 of the author's statements. " Inside the earth is a hollow region 

 large enough to hide the moon and to spare." " The earth's axis has 

 two openings, one at either Poles (sic)." " Metoric swarms and 

 ether are attracted through the axis, as food. One supports the 

 other. The earth does not lose weight but adds to it. Internal 

 combustion." " All winds and tempests originate at and from the 

 Antarctic pole." " The moon has not yet emerged into adult life. 

 She will do so before long," and it will be " a startling epoch in our 

 history." " The heavenly bodies will increase in number, like 

 nebulae, and produce larger bodies." The pamphlet is furnished 

 with a marvellous diagram of the earth in space. We may safely 

 endorse the author's own judgment on his work, that, " whatever its 

 defects, and they are many, it cannot be said it is wanting in 

 novelty, for from the first page to the last the interest is fully kept 

 up." 



The Age of the Isthmus of Panama 



A reliable account of the geology of Panama has long been one of 

 the greatest of geological desiderata, for, in spite of the surveys for 

 railway and canal, and the repeated traverses of the pass of Panama, 

 it has been very difficult to obtain any satisfactory information as to 

 the last date at which marine deposits were laid down upon the 

 summit of the isthmus. Maack's observations have been repeatedly 

 quoted as proving that Pleistocene marine shells occurred on the 

 watershed, and that therefore there was a free waterway across the 

 isthmus in recent times. This view was supported by the zoo- 

 logists, who, impressed by the general resemblance between the 

 faunas on the two sides of the isthmus, concluded that this could 

 only be explained by a recent direct communication between the 

 two seas. Other workers, however, after a more detailed study of 

 larger collections, have concluded that, in spite of the generic re- 

 semblances, the species of the Carribbean and Pacific are almost 

 entirely different, and that therefore the two oceans have been 

 separated for a considerable period. All students of West Indian 

 geology will therefore be very grateful to Professor Alexander 

 Agassiz, who sent Professor P. T. Hill to Panama to settle 

 this question by direct evidence, so that we are no longer dependent 

 on the inferential methods that hitherto have been only available. 

 Professor Hill's report has been issued as one of the Bulletins of the 

 Museum of Comparative Zoology (vol. xxviii., No. 5). It is entitled, 

 ' The Geological History of the Isthmus of Panama and portions 

 of Costa Rica ; based upon a Reconnaissance made for Alexander 

 Agassiz." The report is accompanied by contributions from Dr 

 Dall, Mr T. W. Vaughan, Mr R. M. Bagg, and others, and is illus- 



