REPORT ON THE PETROLOGY OF THE ROCKS OF ST. PAUL. 29 



EXPLANATION OF THE PLATE. 



Fig. 1. Peridotite of St. PauCs Rocks. General aspect of the microstructure of the rock 

 This section is almost entirely composed of colourless grains of olivine more 

 or less elongated of about O'Ol mm. in diameter, the yellowish-brown or black 

 particles scattered through the section are chromic iron (p. 9) 



Fig. 2. Peridotite of St. Paul's Rocks. This figure represents a section of a specimen 

 with banded structure. The darker stripes consist of a compact aggregation 

 of minute olivine grains and chromic iron particles. The large striated and 

 broken crystal at the upper part of the figure is the section of enstatite, described 

 pp. 14, 15 



Fig. 3. Peridotite of St. Pauls Rocks. The ground mass composed of olivine grains, the 

 yellowish-brown sections are chromic iron (p. 9), the green ones actinolite, 

 described pp. 11 and 12 



Fig. 4. Phosphatic vein in the peridotite of St. PauFs Hocks. Section of a concretion 

 of phosphate of calcium, described pp. 17, 18. The yellowish-brown undu- 

 lating lines are oxide of manganese 



