164 



(a) agree with the Red Head Beds which I thought as old, if not rather older, 

 than the Auchmithie conglomerate. 



You will observe that for my object in introducing the diagram section the 

 unconformable beds {a) were not wanted at all, so it will be unlucky if I was 

 mistaken. 



Look for pebbles and boulders of rolled conglomerate in the Whiteness beds. 

 I cannot find my notes, but I think I saw them and was much struck with them 

 thirty-five or more years ago. 



What you say of the Corncockle Muir footprints being, as we supposed, 

 Permian, is most satisfactory. 



Let me hear as soon as you have been at Whiteness. I am very glad you 

 were so far north as to be able to go there. 



Believe me, very truly yours, 



CHAS. LYELL. 



P.S. — On my old map I see I had marked some strata at Denhead with the 

 same colour as the Whiteness beds ; but I forget all about this. You will see 

 as you go along the coast. I enclose a copy of part of my map. The dips, 

 however, are put in now merely to shew why I thought the Whiteness beds 

 newer than the Auchmithie and Red Head beds. 



The second letter, equally characteristic of the writer, is from 

 Murchison in relation to the same subject. 



28 Jermyn Street, July 8, i86i. 



My dear Harkness, 



I am right glad you are going to examine the Scarabein (rough 

 mountain) composed of the white quartz-rock forming the east of Sutherland 

 and south of Caithness. 



Three times have I examined these rocks. 



jst, in 1827, with Sedgwick, with a view to their relation to the Old Red 

 Conglomerate base, which, on their flanks is a white conglomerate (see Trans. 

 Geo/. Soc, 2nd sen, vol. xi., p. 351. 



2ftd, With Nicol in 1854. 



^rd, By myself in 1858, when I staid with the Speaker [Denison] at Langwell 

 on the Berridale Ness, and 



Lastly, When I took Ramsay with me in 1859, we traversed direct from the 

 west coast, and traced the succession of gneissose strata all along the north 

 coast which are so broken and turned up by intense pressure of granite in its 

 eastern extremity, that nothing is more probable (and 1 have for some time 

 thought so) that a trough might be established. 



As, however, the weather was very rough and wet as we came along the 

 island road from coast at Melvid and Big House to the inn of Achintoul, and 

 thence by Kildonan to Helmsdale (a charming geological road), that independ- 



