594 PROCEEDINGS OF THE ACADEMY OF [NoV., 



These cherts and cherty limestones occur also at Jackass Point 

 in St. John's Harbor. The same character of rock, marly limestone 

 with associated flint and chert, and with corals, etc., is found in the 

 town of St. John's, and is, in fact, the material upon which the cathe- 

 dral is built. At the cathedral it is mostly chert, and the flint and 

 chert are found to the southeast of the town along the roads. Mol- 

 lusks have been reported from this chert, but no species have been 

 determined, although doubtless a considerable fauna will be found 

 in the Nugent collection when it comes to be studied. This last 

 hne of this rock, which runs southeast from St. John's Cathedral, is 

 probably another layer of the marl and chert parallel to the one 

 mentioned as running from Jackass Point southeast to near the 

 sugar factory, one mile south of St. John's. 



It is seen exposed, and fragments of the flint are plentiful along 

 the roads to the southeast of the town, south of the Botanic Station; 

 indeed, it forms some of the small hills in this section. These deposits 

 seem to be more or less discontinuous and are only to be seen where 

 the ground becomes too hilly or the soil too stony for cane culti- 

 vation. 



The "volcanic sands and sandstones," bed D, of Purves are even 

 more discontinuous. They are characteristically developed, as he 

 describes them, along the northwest sea-coast at Dry Hill and at 

 Corbizon Point, where they are overlaid by the "lacustrine chert" 

 of Purves. Traces of these "volcanic sands" are seen in some places 

 to the east of St. John's, but their horizon is only marked in some 

 places by sandy lumps and concretions in the white tufaceous rock. 

 Sands at the horizon for these "D" beds are seen in patches from 

 Corbizon Point to the southeast, into the interior of the island; but 

 that they are often wanting, as may be seen on the hills east of the 

 Botanic Station, where a continuous section of the white tuffs, some 

 with sandy modules or concretions representing the horizon of 

 "D," the "volcanic sands," is overlain by the "lacustrine chert" 

 with fresh-water shells imbedded in its mass. At the Public Ceme- 

 tery, also, the sands are wanting, only the sandy nodules mark the 

 horizon of these beds. The white tuffs above the "marine chert" 

 are sometimes partly replaced by the lenticular masses of the volcanic 

 sands, or sometimes these sands are entirely wanting. These white 

 tuffs owe their color to kaolin from the alteration of feldspar in the 

 volcanic ash, and are mixtures of ash (usually fragments of feldspar) 

 and kaolin. The admixture of kaolin becomes so plentiful in the 

 upper beds that the rock might be called either a water-deposited 



