96 



BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



stretch of coast between Mosquito Cove aud the east point of Lucea 

 Harbor. Here the highway is located upon a narrow strip of low coast 

 plain, following an inland bluff vvhose base, to a height of 30 feet, is 

 composed of the black shales of the Richmond beds, which stand almost 

 vertically. Above these is a firm scarp rock of old Soboruco 30 feet 



SjL 



Figure 32. Bluff, "West Bank of Mouth of Great River, near Round Hill 



Point, Montego Bay. 



a. Back coast country of old White Limestone. 



b. Yellow Marls allied to Manchiorieal Formation. 



c. Soboruco near sea level. 



thick. This Soboruco is made up of gigantic coral heads of many spe- 

 cies, as shown on Plate XXIX. The heads are embedded in a matrix of 

 dirty white and yellow marl, and have been so altered by induration 

 and crystallization that they could be broken by the hammer only with 

 great difficulty. The summit of this reef constitutes a level which is 

 visible for several miles. It corresponds in altitude, thickness, and 

 lithologic character with that elsewhere noted at the mouth of Priest- 



FiouRE 33. Old Reef unconformable on Old Eocene Clays near Barbican. 

 a. Subvertical Richmond Formation. 

 h. Reef Rock. 



man Ilivor near Northeast Point in Portland. This Soboruco is the 

 oldest not only by occurrence, but also in appearance ; the coral heads 

 are more con-solidated and crystallized, and the embedding material is 

 of a yellow color indicative of long oxidation. The unconformable con- 

 tact of this old reef with the almost vertical Richmond beds is clearly 

 shown in a bluff over 100 yards in length. 



