GEOLOaY OP TRINIDAD AND ClENPUEGOS KEGIONS. 73 



tion of the dip and the faultmg. it is not practicable to measure the thick- 

 ness, which, however, must be considerable, for the formation underlies 

 much of Trinidad valley, which is 3 miles wide and 18 miles long. 



Overlying the sandstones, there are some limestone beds, succeeded by 

 other beds of sandstone, which in turn are surmounted by heavy masses 

 of limestones. The sandstones are fossiliferous. A flag-like plant, re- 

 sembling Ttjpha (identified by Mr Knowlton), was collected, but the 

 formation was not carefully searched for fossils, which are found in the 

 same series west of the mountains. 



As best exposed at the railway tunnel the overlying limestones occur 

 in undulating and very much broken and jointed beds, so that the dip 

 cannot be everywhere defined, but where recognizable the direction varies 

 from 20° to 45° west of south. The inclination of the beds diminishes 

 toward the northern end of the section. The rock is a fine grained, com- 

 pact and semicrystalline limestone, of drab color chiefly, but yellow 

 and whitish tints also occur. The general appearance is older than that 

 of the Tertiary limestones. Some conglomerate is included in the lowei 

 beds at the tunnel. The thickness reaches a few hundred feet, but a 

 close determination is not possible. The highest altitude at which these 

 beds were seen reaches 400 feet above tide, where they dip 40° south, 60° 

 west. The exposed and fissured surfaces are often thickly coated with 

 incrustations of ferric and manganese oxides. 



Ciei'ifuegos region. — The same formation occurs on the western side 

 of the Trinidad mountains, and has been well described by Mr G. F. 

 Mathew in the paper already cited. As this paper is not easily obtained 

 the writer feels justified in quoting freely from Mr Mathew's work, as his 

 observations are confirmed : 



" On both sides of the Damuji a series of strata is exposed, consisting chiefly of 

 limestones, but apparently separated into two bands b}^ an intermediate body of 

 sandstones. . . . The limestones . . . cropping out of the ridge west of the 

 Damuji are clearly underlain by sandstones holding Cretaceous fossils, and, although 

 subcrystalline, fine grained and homogeneous, cannot be regarded as primary. Their 

 lower beds are gray and impure, but did not yiekl any recognizable fossils; the 

 gray grits and sandstones, however, upon which they rest contain shells of the 

 genera Coims and Oliva, several small, undetermined bivalves and a number of 

 small echinoid forms resembling Ciderites. These organisms were observed in the 

 sandstones on the hillside, just above the buildings of the Constancia estate, where 

 both the limestones and sandstones dip westward at a very low angle. I was in- 

 formed that the subcrystalline limestones of this group rise to the surface in the 

 Zapata sw^amp (which the writer has seen near Yaguaramas). . . . 



" I observed the arenaceous strata of this region at two points in the river valley, 

 which would, if connected, carry them diagonally across the stream. The first of 

 these places met with in ascending the river is the passa or ferry on the Cienfuegos 



