hill: geology of JAMAICA. 83 



having a tliickness of 200 feet as measured in the bluff upon which 

 Captain Baker's house at Port Morant stands. The loose gravels at the 

 base of this section have a very recent appearance, a deception which 

 is further aided by the fact that the}'' occur at beach level, and contain 

 perfectly preserved fossils resembling modern shells. The fossils here- 

 tofore reported from Bowden are found in the gravel bed, and, less 

 abundantly, in a few feet of the lower part of the overlying marls, at 

 the foot of the hill, at the beginning of the road leading up the hill to 

 Captain Baker's, and in such abundance that as many as 400 species of 

 Mollusks have been determined by Dr. Dall from two barrels of material 

 collected by Messrs. J. B. Henderson, Jr., and C. T. Simpson and the 

 writer. A few specimens occur higher up the hill, while near the summit 

 there is a body of firm crystalline secondar}^ limestone containing moulds 

 of the characteristic fauna. The physical characters of this formation 

 can be traced from Bowden to Morant Bay and beyond nearly to Yal- 

 lahs Island, but there it loses its identity. On the road from Bath to 

 Bowden its position above the Cambridge beds is fairly well revealed. 



The stratigraphy of the formation has not hitherto been presented 

 correctly, although in the Jamaican Reports under the name of the 

 " Yellow Limestone " it was partially confused with the entirely differ- 

 ent beds herein described as the Cambridge formation, and the gravel 

 beds were mapped with the Pleistocene and recent formations.^ Hence 

 its identity as a formation did not appear in these Reports.^ 



It is only on the south coast of the east end of the island that 

 the Bowden beds have the characters mentioned. It is evident that 

 the formation with modified lithologic features occurs elsewhere on the 

 island, for the Bowden fossils have been found on the opposite side by 

 us, and reported from round the district of Vere near the coast of 

 Clarendon by other writers, in formations of quite a modified lithologic 



1 Careful search of Barrett's writings show that he made two brief references 

 to tiiese beds. In one place (Jamaican Reports, page 44) he merely mentions 

 "beds of marl, sand and conglomerate of the Bowden series," and alludes to sec- 

 tions and further descriptions to be given, but which were never published. 

 Upon another page (Ibid., pages 45, 46), under the head of "gravels, clay, and 

 yellow marl," he gives the following account of what we now know as the typical 

 Bowden locality : " On the northeastern portion of the Port at Bowden we find 

 the upper beds both thicker and more inclined (10° S. E.) than on the west, and are 

 also more fossiliferous. Below the Pteropod marl are beds of the most perfect 

 Tertiary sliells yet known on the island." 



2 The fossils of the Jamaica Survey from Bowden in the Museum at Kingston 

 are also labelled the " Yellow Limestone." 



