312 REVIEWS 



along the Atlantic coast during the late Mesozoic and early Cretaceous 

 time. 



Regarding the criteria of correlation which were followed the 

 author significantly remarks : 



"As the different methods of correlation are examined in retrospect, 

 the interdependence which exists between the various classes of 

 physical and biological criteria becomes clearly manifest. 



"The faunal and floral characteristics of a formation find their full 

 interpretation only as the physical factors are clearly understood, since 

 the geological and geographical range of forms is determined to a large 

 extent by conditions of sedimentation. The physical characters of a 

 formation therefore bear a close relationship to its contained fossils, 

 and cannot be ignored in the correlation of the deposits. 



"Although the most trustworthy correlations are based upon 

 palseontological data, the possibilities of variation in the succession of 

 organic forms, in two distant areas, are so great that detailed correla- 

 tions can seldom be satisfactorily attempted, even where general 

 equivalence is recognized. 



"The geologist, therefore, must take into consideration both the 

 geological and the palseontological criteria in the correlation of the 

 sedimentary rocks. No class of facts can be ignored." 



Charles R. Keyes. 



The Elevated Reef of Florida. By Alexander Agassiz. With Notes 



071 the Geology of Soutliern Florida. By Leon S. Griswold. 



Bull. Mus. Comp. ZooL, Vol. XXXVIII, No. 2 (pp. 29-62, 



26 plates). 



The work upon which this double paper is based consists of a trip 



made by Mr. Agassiz somewhat over two years ago, and one made by 



Mr. Griswold early in 1896. The purpose of the latter was to clear up 



if possible, some of the obscurity which surrounds the geology of the 



Everglades. The paper opens up much that is new in the story of the 



organic portion of the peninsula; and it is to be regretted that low 



water prevented Mr. Griswold from reaching Long Key, which was 



one of the most important goals. 



The reef has been elevated from six to twenty feet, the amount 

 decreasing southward. At Key West the coastal plain is found at a 

 depth of 50 feet (Pliocene), while Eocene strata are 700 feet from the 



