I 



O-S THE GEOLOGT OF BAEBADOS, 173 



(a) Chdllcy Earths and Calcareous Marls. 



Near Codrington, basement bed. 



Cfinefield e&tate, basal chalk. 



Clelaiid Hill, uppermost chalky beds, two samples 5 and 10 feet 



below the coral-rock. 

 Olton's Cave, 44 ieet below the gully-floor (sent by Mr. E. 



Easton, C.E.). 

 Granular marl, from the knoll at the top of Eissex Hill. 



All these appear to be nearly pure foraminiferal deposits, though 

 in the first four the area occupied by more or less perfect tests is 

 small compared with that occupied by fine calcareous material. 

 This tine material will be fully described in the sequel ; it forms 

 the matrix in which the larger constituents are embedded. In 

 these chalky earths the predominating foraminifer, and the only 

 form visible in thin sections, is a Globigerina, but after washing 

 some of the material several other genera and species were found 

 to occur. Kadiolaria are rare, but a few sponge-spicules can be 

 seen. All the specimens contain a few mineral grains. 



The last on the list presents different characters. It has a 

 granular aspect, is rather light in weight, greyish buff in colour, 

 and having little cohesion the mass breaks down on slight pressure. 

 Examined in thin section it is seen to consist almost eutii'ely of 

 Globic/erince, their tests being closely crowded together, and very few 

 other forms being visible. The matrix which tills the interstices is 

 largely composed of separate calcite-crystals of irregular shape. A 

 few coccoliths are present, and a small quantity of inorganic material, 

 apparently broken felspar-crystals and volcanic glass. 



(b) Calcareo-siliceous Marls. 



Pico Teneriiffe, on the north-west coast. 



Melvin's Hill (base). 



Airy Cot, base of Mount Hillaby. 



Mount Hillaby, summit of southern peak, and 10 feet below. 



Cleland Hill. No. 2. Hard chalk above basal limestone. 



duff's estate, on the north coast. 



The rocks occurring in these six localities are largely calcareous, 

 but a number of radiolarians are visible in all of them. The Pico 

 Teneriffe specimen is the most calcareous, but appears weathered, 

 and foraminiferal tests are more faintly outlined than usual. In 

 all the specimens the greater part of the calcareous matter is very 

 fine. In Cleland Kill and ClufF's few foraminiferal tests can be 

 seen in section, while it is evident that many forms which show 

 strongly are radiolarians, though their siliceous skeleton is often 

 obliterated and their outline only is preserved. 



All contain, especially those from Mount Hillaby, Cluff's, and Mel- 

 vin's Hill, minute, angular mineral-fragments, the largest of which 

 measure about -02 mm. in their longest axis. 



