502 MR MILNE ON THE GEOLOGY OF ROXBURGHSHIRE. 



knowledge of the subject, digging up several spadefuls and pointing out the component parts of the gra- 

 nite, and by convincing me that the hill in front of the Manse, from which the materials for making the 

 road, along which you and Dr B. went on the morning you left, was almost entirely constructed of the 

 same substances. To-day, for he is making some repairs on the Manse, he drew my attention to the 

 decomposition of rocks, by crushing with his foot several blocks of weathered granite, and then comparing 

 them with the adjoining soil, and fully demonstrated, to my satisfaction at least, that the two substances 

 were precisely the same. You will also notice that red granite is found, and that the soil is composed, 

 of a greater proportion of that than of the grey. You mention that Criffell is distant 20 miles from this, 

 but if you say 40, from where I write, you will come nearer to the truth, and find that the valleys of 

 Nith, Annan, Esk, Tarras, and Liddell intervene, and present many barrier acts, to the establishment 

 of Dr B.'s theory. 



'' THOMSON has been very active in collecting specimens- If you want more, he or I will furnish 

 them with great pleasure. I hope those sent will arrive in safety." 



