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THE OTTAWA NATURALIST 



Vol. XXIII. OTTAWA, AUGUST, 1907 



NOTES ON THE GEOLOGY AND MINERAL RESOURCES 

 PjOF TRINIDAD AND BARBADOS, B. W. ISLANDS. 

 By R. W. Ells, LL.D., Etc. 



Summary of paper read before Royal Society of Canada, May, 1907, 



The islands of Trinidad and Barbados are among the most 

 southerly of the Windward island group of the West Indies. The 

 former lies a few miles off the north coast of South America, 

 opposite the mouths of the Orinoco r^'er, with an area of 1,7 50 

 square miles, and a population of about 2 55,000 ; the latter, about 

 200 miles to the north-east, withan area of 166 square miles, and, 

 with a popttlation of rather miore than 1 ,200 persons to the square 

 mile, can rightly be considered the most densely populated 

 country in the world in so far as now known. 



The geology of both these islands is quite simple. In 

 Trinidad, the northern portion from the passage separating the 

 north-west corner from Venezuela, known as the Bocas, to the cape 

 at the north-east extremity, is occupied by a range of hills with 

 elevations rising in places to more than 3,000 feet, composed of 

 slaty and schistose rocks with occasionally areas of limestone. 

 The schist is cut by veins of quartz, generally of small size. in 

 which traces of gold are foimd, while the presence of iron has also 

 been recognized at several points. These schists are the oldest 

 rocks in the island, and resemible the lower Cambrian of Canada in 

 miany respects. 



South of this and comprising by far the greater part of the 

 island the rocks are much more recent, consisting for the most 

 part of shales and sandstones of Tertiary age, with possiblv small 

 areas of underlying Cretaceous, especially along the southern 

 flank of the mountain range. These Tertiary rocks comprise 

 large areas of oil-bearing sandstone, and the formation as a whole, 

 is thrown into a series of folds or anticlines, of which four principal 

 ones have been recognized as extending in a general east and w^est 

 direction across the southern part of the island, with several 

 secondary ones. Along the courses of all these, oil-springs, out- 

 flows of asphalt or thickened petroleum and occttrrences of 

 natural gas are frequently seen, with mud volcanoes which 

 indicate the escape of the gas in large quantity. 



The most northerly of these anticlines, yet definitelv re- 

 cognized, comes to the west coast at the town of San Fernando 



