162 Archdeacon Verschoyle on the Geology of the North Coast of 



in conformable stratification. At Balderig Inlet the mica slate disappears^ re- 

 curring- no more on the coast. 



The inferior rocks, granite, gneiss, mica slate, and quartz, just described, 

 frequently graduate so insensibly into each other, that the observer is inclined 

 to allow them a common origin, modified only by variations in the proportions 

 of the ingredients of which they consist ; for instance the Erris granite in 

 most instances passes into gneiss, the gneiss into mica slate, and this into 

 quartz rock. Below the signal tower of Tarmon, veins of that granite, how- 

 ever, pierce the mica slate, producing decided and obvious proofs of protrusion 

 and derangement, and at the exposed junction of these rocks the mica slate is 

 unconformable in stratification, the edges of its layers abutting against the 

 inclined face of the granite. 



I. The Trap Rocks, Porphyry, and Basalt. 

 These are the most interesting and remarkable rocks of the district. They 

 form dykes, unexampled, I believe, for length, directness, and parallelism, 

 and for their varied effects on the adjacent strata*. Their strike is nearly east 

 and west, differing only 4° or 5° to the north of west. I commence their de- 

 scription with the most northerly, which may be distinguished as No. 1.; and 

 proceed with my details in a direction from west to east. 



No. 3. 



Strata of mica slate bent over projecting masses of trap at Attatovick Point. 



* See Map, Plate XI *. The points at which the dykes were actually seen are marked by a 

 line ; and the supposed connexion or continuation by dots. 



