1873.] junn — ttie skcondary rocks of Scotland. 120 



and relations of this patch to that of Stotfield, and the nature of the 

 rocks which compose it, so greatly resembling the coarse grits 

 and conglomerates of part of the unfossiliferous Lower Oolites of 

 Sutherland, strongly suggest that the Burghead beds may be of the 

 same age as those of Stotfield ; but hitherto, unfortunately, no fossils 

 have been found in the former. 



At various points throughout the peninsula which lies between 

 Burghead and Stotfield Heads, interesting strata of Triassic age are 

 exposed, as will be described hereafter. The district is traversed 

 by a series of great faults ranging N.N.E. and S.S.W., as shown by 

 Professor Harkness *. By far the larger part of the area being 

 deeply covered with drift, above which only a few ridges of the 

 hardest rocks appear, it is possible that other patches of the Jurassic 

 rocks may be preserved within it, though hidden from our obser- 

 vation ; in the Boulder-clays of the district fragments and immense 

 transported masses of the Liassic and Oolitic rocks are particularly 

 abundant. 



Having now described the general position and relations of the 

 several patches of Secondary strata in the north-east of Scotland, it 

 is necessary to refer to a peculiar phenomenon presented in them, 

 and which has been already described by several geologists. I refer 

 to the existence of pseudo-dyl-es among them. These present all 

 the external forms of dykes of igneous rock, running in a more or 

 less vertical direction across the several beds, and sending off various 

 branches and offshoots in their course. When the nature of the 

 rock of which they are composed is examined, however, it is found 

 that, instead of being composed of materials of igneous origin, the 

 rock is certainly an aqueous one, an indurated sandstone or a cal- 

 careous grit. These pseudo-dykes occur at Eathie f , Kintradwell J, 

 and in the Brora coal-field §. Two important facts tending to eluci- 

 date this subject were noticed by Hay Cunningham and Hugh 

 Miller respectively. The former showed that in the fine example 

 at Kintradwell, fragments of carbonaceous matter occur, and that 

 these are arranged, not horizontally as in the associated heels, but 

 vertically and parallel to the sides of the dykes || ; the latter found an 

 Oolitic shell enclosed in one of the dykes at Eathie %. During my 

 own survey of the district, the only fact of importance which I was 

 able to add to those accumulated by previous observers was, that at 

 Eathie some of the most important of these pseudo-dykes run along 

 the axes of the anticlinal folds of the contorted strata. 



These pseudo-dykes always traverse greatly disturbed or con- 

 torted strata. That they have been filled from above is clear, as 

 pointed out by Hugh Strickland ; but that the fissures in the soft 



* Quart. Journ. Geol. Soc. vol. xx. (1864) p. 431, fig. 1. 



t See H. E. Strickland in Trans. Geol. Soc. 2nd ser. vol. v. p. 599. 



J Murchison, Trans. Geol. Soc. 2nd ser. vol. ii. p. 304. Cunningham, ' Geo- 

 gnosy of Sutherlandshire ' (1839), p. 36, plate vii. fig. 2, note G. 



§ Murchison, Trans. Geol. Soc. 2nd ser. vol. ii. pt. 2. p. 301. 



|| Op. cit. p. 36. 



«[ Sketch-book of Popular Geology (1859). p. 305. 

 VOT,. XXIX. — PART I. K 



