GTBB OYSTER CONGLOMERATE BED AT BROMLEY. 327 



the oyster-conglomerate, mixed with, rolled flints of various sizes, from 

 that of a pea to a potato, varying in thickness from three to fourteen 

 inches, upon which succeed thin layers of sand and pebbles for three 

 feet, and lastly, the gravel, which varies from two to twelve and 

 eighteen feet in depth. These are better represented in the following 

 table : — 



Ft. In. 



1 Gravel two to twelve feet and 18 0 



2 Layers of sand and pebbles 3 0 



8 Oyster-conglomerate, mixed with small and large rolled 



flints, varying from three inches to 0 14 



4 Light brown and variegated sands, with a few pebbles and 



a few shells, thinning out two inches to 0 3 



5 Brown sand and pebbles, free from shells in layers, also 



dying out 0 14 



6 Variegated brown sand, with a few pebbles three 



feet to 4 0 



7 Very light brown sand, with small pebbles and shells .... 0 16 



8 Light brown sand with fragments of small shells 0 12 



9 Light grey uniform sand, averaging 12 0 



In that part of the excavation, situated towards the north, and which 

 is at the same time the most elevated, the surface is a mixture of drift, 

 sand, and chalk- detritus, overlying layers of sand and plastic clay form- 

 ing the conglomerate. The depth of this drift may be from six to eight 

 feet, and corresponds with the beds 1 and 2 in the foregoing table. 

 Then for twenty-five feet are seen layers of sand and pebbles alternating 

 with the oyster conglomerate rock, in which multitudes of shells are 

 found forming a hard sort of breccia, which varies in thickness from six 

 to eighteen inches ; and, in some places, consisting wholly of pretty 

 large or of small rolled flints, and in others wholly of masses of oysters ; 

 in others, again, of myriads of small shells, some in fragments, and 

 others quite perfect, but very friable. In some of the layers, the con- 

 glomerate has assumed the characters of a distinct sandstone, and is 

 extremely hard; and when it consists of small pebbles, forms a 

 pudding-stone. To these succeed the layers marked 4 to 9 in the 

 table, but they were not completely exposed in the northern part of the 

 excavation. The annexed diagram gives a section of this place. 



