Tlie Cretaceoiis and Tertiary Question in Jamaica. 423 



The accompanying table is intended to show at a glance the names 

 that have been given to the different formations in Jamaica since the 

 time of De la Beche in 1827, together with, in the last column, the 

 terminology that I suggest might be most conveniently applied to 

 them. 



The first column of De la Beche ^ was drawn up before any of the 

 Cretaceoiis Rudistce were discovered in Jamaica. The map accom- 

 panying the report comprises only the eastern portion of the island, 

 including the Blue Mountain district. His Coal Measures refer 

 apparently to an exposure of Carbonaceous Shales (Richmond beds) 

 to the south of Port Antonio. His Trap Eocks are associated with 

 those mentioned just below, namely, the Submedial or Transition, 

 which is the term he uses to designate the Blue Mountain series. 

 Sawkins's term, Trajipean, apjjears to have been borrowed from 

 De la Beche's earlier designation. 



Sawkins's column is the one generally employed by English 

 geologists, though it must be remembered that his term Yellow 

 Limestone includes also the Bowden beds, which, as will presently 

 be mentioned, are later than the White Limestone. 



Hill's column is the one in general use in American literature, 

 and he has employed the custom of giving more or less non-committal 

 place-names to the various beds, a procedure which seems hardly 

 necessary in a locality such as Jamaica, whose formations had been 

 so well worked out by Sawkins more than thirty years previously. 



His terms Cambridge and Catadupa formations, founded, as I shall 

 presently show, on a mixed collection of Cretaceous and Eocene 

 fossils, must be abandoned. The terna Chapelton may be retained 

 if it be used to designate the Yellow Lim.estone of Eocene age, since 

 this bed only forms the hill on which the village of Chapelton is 

 built. 



The Cretaceous portion of his Cambridge and Catadupa beds is 

 equivalent in age with parts of his Jerusalem, Logic Green, Ballard, 

 and Minho beds. Curiously, however, the rock that occurs actually 

 at Cambridge and Catadupa railway stations is the Yellow Ijime- 

 stone, while the succession of the Rudist and Yellow Limestones 

 is seen along the line between these two points. 



The statement of the mingling of faunas in the Richniond, 

 Cambridge, and Catadupa beds has crept into general literature, 

 though the occurrence of Rudistce and Eocene fossils together is 

 reasonably questioned by some authors.- 



Position of the Bowdex Beds. 



An error arose during the time of J. G. Sawkins, G. P. Wall, and 

 the other geologists who surveyed the island between the years 

 1861 and 1865. This had to do with the position of some of the late 



^ " Remarks on the Geology of Jamaica " : Trans. Geol. Soc. London, 1827, 

 vol. ii, No. 36. 



2 E. Haug, Traiti de Geologic. II. Periodes Gi'ologiques, p. 1525. 



