ON THE GEOLOGY OF BAEBADOS. 



207 



The base is not seen, for the boundary appears to be a fault, but 

 a strong spring issues at or near their junction with the black bitu- 

 minous claj^s of the Scotland Series. There have been many slips 

 down the slope, but the true dip seems to be a fairly steep one, 12° 

 or 15° to the south-east. The lowest beds seen yielded on analysis 

 57 per cent, of carbonate of lime, and are therefore more calcareous 

 than the greyish beds near the base of the series by Conset Bay, 

 though not so chalky as the basement-bed there ; we infer that they 

 are about 20 or 25 feet from the base. 



West of Castle Grant the cliff of coral-rock ends suddenly, the 

 border of the coral retreating to the gully below Mcolls, and from 

 beneath it rises a mass of red, pink, and yellow, soft argillaceous 

 earth, which is purely siliceous though almost destitute of radiolaria. 



Pig. 3. — Section from Chimborazo to Castle Grant, 

 N.W. S.E. 



Chimborazo. Castle Grant. 



[Distance one mile.] 



a. Scotland Beds. c. Coloured clays. 



h. White earths. d. Coral-rock. 



These clays appear to have a thickness of about 40 feet, and are 

 succeeded to the westward by the dark, sandy, bituminous clays of 

 the Scotland Series, which thus rise to the top of the slope about 3 

 furlongs north-west of Castle Grant. 



The yellow earths have the appearance of overlying the Scotland 

 Clays by the road, but we believe they are faulted against one 

 another (see fig. 3), for otherwise we cannot account for the 

 white earths which underlie the coloured group everywhere else. 

 The level of the outcrop of these red clays west of Castle Grant is 

 about 1050 feet. 



From this point the Scotland Beds form the whole of the main 

 ridge and slope as far as Chimborazo Mill, the outcrops of the 

 Oceanic Deposits being thrown back to the southward and forming 

 a second escarpment of moderate height, capped by a low cliff of 

 coral-rock. 



Below Chimborazo House another fault brings in a greater thick- 

 ness of the series, the base of the Oceanic Deposits lying some way 

 down the northern and western slopes of the hill. The result of this 

 and the Castle Grant fault has been to lift a block of the Scotland rocks 

 to a high level between the two tracts of Oceanic Deposits (as shown 

 in fig. 3). In the hollow where the fault runs there are red and 

 yellow clays probably faulted in, but their occurrence shows that 

 the total throw is about 240 feet. 



