TJie Cretaceous and Tertiary Question in Jamaica. 427 



that he made two traverses of the line for the purpose of collecting 

 the fossils on which his conclusions were based, and his lists of the 

 fossils ^ from near Catadupa and Cambridge, based on the 

 determinations of T. W. Stanton, certainly indicate a mixture of 

 forms of the Yellow and Rudist Limestones. 



I feel sure that only a prolonged and detailed mapping by some 

 geologist residing on the spot would clear up the tectonic structure 

 of this district of Jamaica. 



■RL. 



Fig. 2. — Faulted junction of Rudist and Yellow Limestone with a crushed 

 shale intervening ; on side of a stream under the railway about a mile 

 soutli of Catadupa station. E.L. Rudist Limestone full of fossils, much 

 brecciated at B. Sh. Slickensided Shale. Y.L. Yellow Limestone with 

 casts of gigantic Cerithia near the top. Height of section about 

 20 feet. 



For a distance of about 3 miles south of Cambridge station, where 

 the actual railway cuttings are deeper and more continuous than 

 they are to the south of Catadupa, I made a sketch of the section of 

 the rocks exposed along the line for about a mile and a half, which 

 show very clearly the relation one to another of the different beds 

 (Fig. 3). These include the sbaly Yellow Limestones full of the 

 Anomia-like bivalve Carolia ; the Yellow Limestone, with large 

 specimens of Ceritkium and Lucina ; red shales with badly preserved 

 fossils ; Rudist Limestones, with " Caprinida " gigantea and many 

 other forms ; and shales with Trigonia, Roudairia, and other 

 Cretaceous fossils that underlie them and form the higher part of 

 the so-called Trappean Series of Sawkins. Overlying one or other of 

 these beds one finds masses of the great White or Cockpit Limestone, 

 of supposed Oligocene age. 



In this section of one and a half to two miles the beds are not 

 seriously alTected by faulting, and the Yellow Limestone follows the 

 Cretaceous Limestone with approximately the same dip and with 

 only a few feet of red shales with indeterminable fossils separating 

 them. This gives an appearance of the conformity of the Yellow 

 and Rudist Limestones in this area, which is liable to lead to a false 

 inference, since in other areas a great thickness of Carbonaceous shale 



1 Loc. cit., p. 129. 



