44 



GEOLOGY or THE CAMPSIE HILLS. 



ference, and is entirely formed of lava and other 

 volcanic productions. In the interior of this 

 island, there is a mountain of considerable height, 

 upon the summit of which may be traced the 

 principal crater of this now extinguished vol- 

 cano. 



The form of this crater is a regular cone in- 

 verted, and its lip nearly measures half a mile in 

 circumference. From this mouth, and from its 

 sides, have flowed many streams of lava, some of 

 which may still be traced in various directions. 

 Where these streams had flowed over planes 

 slightly inclined, their surfaces in general con- 

 tinued to be tolerably smooth ; but where descents 

 were more rapid, there in many places, the sur- 

 face-crust of the lava had burst, and in such a 

 situation, it presented a broken, rough, and rugged 

 appearance. 



One of these streams of lava, I was enabled to 

 trace until it arrived at the verge of the island, 

 where it had dropt into the sea over a lava rock 

 nearly perpendicular, and which rose from the 

 level of the water to a height of not less than 

 from sixty to seventy feet. The lava here, even 

 after it had passed over the verge of this precipi- 

 tous declivity, still retained for a short distance a 

 considerable degree of smoothness, but which was 

 soon broken in upon by narrow longitudinal fur- 

 rows appearing upon its surface. These lines at 



