48 bulletin: museum of compaeatiye zoology. 



subdivision of the Blue Mountain Series, and with all its variations is 

 quite different from the Richmond beds of the upper division. 



In general, the Minho beds correspond in character with the " Trap- 

 pean Series and Purple Shales and Conglomerate Formation " of the 

 Jamaican Reports, occurring extensively from Clarendon eastward to 

 Bath in St. Thomas, and notably near Gordontown, back of Kingston, 

 in the ribbed salients (cuchillas) of Newcastle, and in Metcalfe. These 

 beds are marked by great abundance of gravel and tuffs and purplish 

 colors. They are placed in our section below the black shales and con- 

 glomerates of th3 Richmond beds, not above, as in the final tabulation 

 of the Jamaican Reports. 



The Fossiliferous Beds of the Lower Division of the Blue Mountain 

 Series. — The massive limestones occur lower in the series in more or 

 less isolated and widely separated outcrops, nowhere of great thickness, 

 and characterized by the Rudistean fossils. 



The Jamaican Reports treat of the fossiliferous Cretaceous beds in- 

 cluded in the series as a single formation. It was described ^ as com- 

 posed of two varieties of strata constituting an upper and lower part. 

 The former was said to consist of marls and sands with corals and many 

 Hippurites, the latter of compact massive limestones with many Radio- 

 lites and Barrettia. These statements are misleading. It is true that 

 the oldest fossiliferous Cretaceous rocks exposed are limestones, and that 

 the marly beds with Cretaceous fossils, of which there are several 

 horizons instead of one, occur higher than the limestones ; but these 

 beds are merely incidents in the great series of volcanic tuffs and 

 conglomerates with which they are interbedded, as is seen in the details 

 of the Clarendon section. No. 2 of the Clarendon section with Creta- 

 ceous fossils is the lowest limestone. These are overlain by the Frauken- 

 field tuffs. Above the latter appear fossiliferous beds of the Logic 

 Green, ^ and Ballard clays which in turn are covered by the Minho 

 tuffs. 



The Cretaceous limestones are found in several other places on the 

 island. Sometimes a limited mass occurs in a manner to create doubt 

 as to whether it is a bed, a local lens, or a great transported boulder; 



1 Jamaican Reports, p. 26. 



2 Local beds of yellow marl and impure segregated limestone are also exposed 

 near Trout Hall on the Minho, and at Pennant's Great House on the St. Thomas, 

 and consist of a considerable thickness of the unctuous yellow clays and segre- 

 gated limestone lumps with numerous specimens of smaller Rudistes (including 

 many of the species described by WhitlSeld) and corals. 



