78 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
With the probable exception of the Mile Gully ridge, nearly the whole 
surface of the northern half of Manchester Parish, as crossed in a north- 
west and southeast direction by the Jamaican Railway line, between 
Porus and Phoenix Park, is composed of the stratified beds of the 
Moneague formation similar to the exposures at Ipswich, and consists 
of alternations of hard compact limestone, dull gray-white in color, semi- 
crystalline in texture, with alternations of white calcareous chalky marls. 
The beds are quite cherty in places, which, with their stratigraphie prox- 
imity, suggest the nearer relationship of these beds to the Montpelier 
than to the Dowden formation. Casts of fossil Mollusca and small 
single stems of branch coral like those found at Retreat also occur. 
These beds are especially well displayed in the cuttings of the river 
near Williamsfield. 
At Ewarton the railway terminal is quarried out of the beds which 
occur in massive uniform layers several feet thick. A few molluscan 
fossils weather out upon the surface of the rocks, but they are too indis- 
tinet for identification. From Ewarton to Moneague the beds can be 
seen from the highway, arching over the western border of the St. 
Thomas basin. At Moneague they have wide surface development, 
especially to the westward via Brownstown, Stuart Town, and Retreat. 
At Ipswich and thence on towards Catadupa the regular bedding is 
beautifully seen in the deep railway cuttings, as shown in Plates XXV. 
and XXVI. 
We are not prepared to state positively that tho beds of theso differ- 
ent localities are identical, for paleontologic material is very rare, but 
from their resemblanee we incline to think that future research will 
show them all to be parts of the same formation. 
The Cobre Formation. — Between the town of Bog Walk," on the south 
side of the interior basin valley of St. Thomas-in-the-Valo, and Spanish- 
town, on the Liguanea Coastal Plain, the Rio Cobre cuts a canyon through 
a white limestone plateau separating the two localities. This canyon, 
known as Bog Walk, is one of the great scenic features of Jamaica, and 
terminates at the Liguanea Plain as a true boca,? from which it took 
its original name, Boca del Agua. 
The canyon of the Cobre is about 200 to 300 feet deep, with sloping 
sides, a fine view of which is shown in Plate X.; it is cut entirely out 
of certain problematic beds of white limestone, which will be described 
1 English corruption of Boca del Agua. 
? Among other uses Boca is applied to the mouth of a canyon debouching upon 
a plain. 
