500 PEOF. J. W. SPENCER ON THE GEOLOGICAL AND [NoV. I9OI, 



thickness in places to onl}- a few feet, or even to espose the 

 underlying rocks, being, however, unmistakably preserved in 

 the depressions of the older surface. 



The materials of the Priar's Hill Series have not been trans- 

 ported to any considerable distance. For this reason, and ou 

 account of the fragmeutal character of the tuffs, as well as perhaps 

 on account of the subsequent denudation, the evidence of the 

 submergence to 200 feet, during this short epoch of rapid deposi- 

 tion, was not observed in the central portion of the island — unless 

 it be in some of the cherty fragments (containing shells and 

 petrified wood) scattered over the surface — wheie, however, the 

 remains of a still newer deposit occur. 



No fossils belonging to this formation ^ per se have been discovered 

 as yet, but a few waterworn corals of the older beds occasionally are 

 found among the pebbles. While the age cannot be determined 

 from the included fossils, yet from physical considerations and 

 from analogous accumulations with similar relationship — namely : 

 the Matanzas formation of Cuba, the Lay ton of Jamaica, and the 

 Lafayette of the American continent — the Friar's Hill Series is 

 thought to belong to the close of the Pliocene or the early part 

 of the Pleistocene Period. 



IX. The Cassada-Garden Gravels. 



■ Oassada Garden Estate is situated about 2 miles east of 

 St. John's, on the eastern margin of the tuffs, and very near the 

 south-western chain of hills of the White Limestone Series. 

 Consequently, it is somewhat distantly removed from even the 

 newer volcanic rocks of Drew's Hill. At the mill on Cassada 

 Garden Estate is a low eminence rising only about 20 feet above 

 the plain. A chain of similar mounds extends south-eastward. 

 These are composed of somewhat coarse, perfectly waterworn 

 pebbles of igneous rocks, with fresh, compact, undecomposed 

 surfaces. In section, at the pond of Cassada Garden, the gravels 

 are seen to be interstratified horizontally with loam. Mr. Watt, 

 who kindly took me to this locality, had examined the section, 

 shown in the well, sunk through the deposit, and found that it did 

 not exceed 20 feet in thickness, or precisely the height of the knolls 

 above the plain. The gravel-knolls do not attain an elevation of 

 more than 60 to 75 feet above the sea. These deposits, trans- 

 ported from considerable distances, and accumulated by currents, 

 have also suffered denudation. The whole series resembles 

 sections of the Columbia formation of America, the Zapata of 

 Cuba, and the Liguanea of Jamaica, which belong to the early 

 part of the Pleistocene Period. 



X. Recent Deposits. 



Many portions of the island adjacent to the sea-shore, as at 

 St. George's Church, directly east of St. John's, have their surface 



^ [Some of the corals studied by Duucan raay have come from these marls, 

 or else from a still more recent formation not yet distinguished on this island, 

 equivalent to the Usine Beds of Guadeloupe.] 



