Vol. 70.] INTRUSIONS NEAR MELROSE. 313 



of trachytic rock, fine-grained at its margin, although it becomes 

 coarser away from the junction. 



The contact of the trachyte with the Silurian rocks is exposed 

 near the path ; but, owing to the striking similarity of the rocks 

 in colour and texture, is most difficult to locate. The Silurian 

 rocks consist of much-indurated coarse and fine bands, greatly 

 contorted and crumpled, which seem to have been pushed aside and 

 diverted from their normal strike. 



A small neck occurs in a ravine between the 800- and 900-foot 

 contours, south-east of Rhymers Grlen. The country rock in its 

 immediate neighbourhood consists of much- shattered red shale and 

 greywaeke. The neck is filled, partly by a bright pink non- 

 porphyritic vesicular felsite saturated with limonite, and partly by 

 a breccia of angular fragments of a pink igneous rock and some 

 bits of sediment in an igneous matrix. 



There are but few exposures in the Faldonside Moor neck. 

 Hillocks of medium-grained ash exist, which in their easterly ex- 

 tension contain numerous fragments of red honeycombed sandstone. 

 The microscope shows a little sedimentary material in the main 

 ash. with pumiceous and glassy igneous rocks, porphyritic and 

 non-porphyritic trachytes, and, most interesting of all, a fresh piece 

 of riebec kite -felsite, containing green-brown biotite. exactly 

 like the felsites of the upper part of Eildon Wester. 



VI. Summary. 



The following are the main results of my recent study of the 

 district : — 



(1) The recognition of the Little Hill basaltic neck within the 

 Eildon Hill complex, the acid rocks of which it almost certainly 

 pierces. 



(2) The extension of Mr. Barron's record of riebeckite. He 

 found this mineral in the Eildon Hills, and suspected its former 

 presence in the Black Hill. It has now been found fresh in the 

 latter, as also in three trachytic dykes half a mile south-west of 

 Cauldshiels Hill, and in a block in the Faldonside Moor neck. 



(3) The recognition of a quartz-porphyry sill in the Eildon 

 complex and a quartz-porphyry dyke in the Chiefs wood neck ; 

 also the realization that quartz is an important mineral in the 

 Eildon complex as a whole, and that the main rock- type occurring 

 there is felsite. 



(4) The proof that, if nepheline occurs in the Eildon complex, 

 it must be very rare. 



(5) The fact that these rocks may be regarded as a link between 

 the phonolites and trachytes of the same age south-east of Hawick 1 

 and those of East Lothian, 2 already so well known. They cannot 



1 H. J. Seymour, ' Summary of Progress for 1900 ' Mem. Geol. Surv. 1901, 

 p. 164. 



- ' The Geology of East Lothian ' Mem. Geol. Surv. Scot. 2nd ed. (1910) 

 p. 127. 



