140 Dr. Berger o« the physical Structure 



sight for an Instant of general views, did not cease to collect 

 in the most patient and judicious manner, observations of detail, 

 which if not in sufficient number to enable us to explain all 

 appearances, have nevertheless the immense value of serving as a 

 compass, and thus preventing ns from making retrograde steps in our 

 researches after truth. 



Though Mullyan is situated completely in the grauwacke slate, 

 we find here and there in the neighbourhood loose blocks of serpen- 

 tine, which indicate a transition country, and similar to that on the 

 east side of the Lizard Point between St. Kevern and Menaccan. 

 The cliffs from Mullyan to the neighbourhood of Loe Pool are the 

 highest I have seen on the coast of Cornwall, especially near Pen- 

 gwinian Point : they form a semicircular line, the regularity of 

 which is broken by angular portions of the rock projecting in some 

 places, and by fissures and indentations in others, exhibiting fine 

 sections of the grauwacke. The continuity of the line is interrupted 

 at Gunwalloe by the mouth of a small river ; through this creek the 

 sea-sand is carried at some distance into the interior of the country^ 

 covering the soil, and heaped together in some places so as to form 

 little sand hills. 



The cliffs become gradually lower as they approach Loe Pool, and 

 the shore is covered with a very fine siliceous sand. At the mouth 

 of the river Loe there is rather a curious fact, and worthy of some 

 remark ; the river forms a kind of reservoir at a little distance from 

 the sea, which I found to be one hundred and sixty paces at low 

 water, from which the water runs into the sea by a subterranean 

 passage. The water in the pool is fresh, though the bar of sand 

 between it and the sea is not more than twenty feet high. This shews 

 that the tides do not rise very high, and the inhabitants assured me, 



