374 MI8CELLANKA. 



Linnapus, and in most recent works is referred to as Parmelia 

 conspersay Hooker, Scot. II., p. bb. 



In the periodical growth of both these lichens we have, if it 

 were recorded on the rock surface, exactly the pattern of the 

 concentric rings, and that some lichens do bore into the rock i- 

 well known. " They act," says Dr. Balfoui*, '' by degi*ees upon 

 the hard rocks, and cause disintegration of their stony pai'ticles. 

 and thus form a stratum of mould in which the seeds of higher 

 plants can find a nidus when wafted tliither by winds or otlui 

 causes." 



"They make a way 

 For bolder foliage nursed by their decay." 



' * Many of them no doubt take up into their substance thi' 

 materials of the rock on which they grow, and when analyzed 

 are found to contain phosphate and oxalate of lime and other in- 

 organic substances." Lecidea geographica is so called from tin 

 peculiar marking it produces on the rocks. 



These quotations prove that lichens do grow in concentric 

 circles, and that some of them, if not all, leave peculiar impres- 

 sions upon the rock where they have grown. 



In 1879, in company with a few of our members, we had ano- 

 ther opportunity of examining numerous specimens of these 

 circular markings at ]{outing Linn and Foi*d Moss. The wind 

 and the rain ai'e playing havoc with these old markings, and it 

 is very evident that they cannot have been exposed many years 

 or they would liave been entirely obliterated before this. They 

 are always on the laminated surface, and most frequently on a 

 sloping surface, and they face the north and west more than the 

 south and east, which is the situation in which many lichens are 

 found. I could find no trace of these circles on the upright or 

 perpendicular fracture of the rock. In a few years more any 

 one going with Mr. Tate's book in liis hand to examine these 

 rocks will be very much disappointed, as they will very soon be 

 entirely effaced by weathering of the stone and other causes. 



The Routing Linn stone is a conspicuous object at present 

 even from a distance. It is a veritable roche moutoniue of large 

 .size for our district, and appears to have been covered or nearly 



