HILL: GEOLOGY OF JAMAICA. 61 
Mollusca are most abundant in the “Bruggadoo,” as the black clays 
at the railway cut where so much slipping bas occurred are called. 
^ 
Chapelton Beds. 
In Clarendon Parish, at Chapelton, and in the slopes of the Minho 
River east of that town, beds allied to the Cambridge formation are 
exposed. These present two subdivisions, the upper of which consists 
of more or less massive beds of yellow foraminiferal (Orbitoidal) marl 
alternating with bedded yellow limestones and grading up into the 
white Montpelier limestones ; the other is mostly composed of creeping 
blue, black, and red clays known in Jamaica as “ Bruggadoo,” resem- 
bling similar material of the Catadupa section, and in whieh occasional 
fossiliferous calcareous layers only an inch in thickness and a few yards 
in length are exposed. 
The higher subdivision has its typical occurrence along the main 
Street of the village of Chapelton, between Chapelton Hill and the River 
St. Thomas. The second is exposed along the “lower” road which 
parallels the foregoing street but follows a lower contour in the valley 
of the Minho. The following local section of this subdivision was ob- 
Served at Chapelton, between the hill in Chapelton upon which the 
residence of the Inspector of Constabulary is situated, and the bed of 
St. Thomas River two miles north. This section is the upward con- 
tinuation of the general Clarendon section given on page 46. The 
thicknesses given are approximated : — 
3. Bed of yellow marl and thin limestone alternating, containing Feet. 
Orbitoides and small Ostrea, estimated thickness . . . +. 185 
in Bius md poa day o o eoe o n n ot ttt s 115 
l. Yellow marl, clay, and limestone . . o n ee. + + 75 
At Mr. Craig's estate in the river valley a considerable mass of yellow 
limestone (No. 1) is exposed, but it was impossible to find determinable 
fossils therein, or to decide the exact position of this mass relative to the 
Clays. It was our impression that it occurred about midway in the 
general section. Down the valley slope, on the so called lower Chapelton 
road, which follows the river and cuts into beds lower than those of the 
above section, many isolated cuts are exposed, composed entirely of the 
blue and purple clays, with an occasional thin local layer of yellow clay 
containing crumbling fossil oysters, Carolia, and Foraminifera. From 
reasons given in the paleontologic discussion, these lower beds are sup- 
Posed to be equivalent to those of the Catadupa section, and the upper 
are a higher extension of the same. 
