Notices of Memoirs — Sir W. Daicson — Eozobnal Structures. 271 



the downthrow side of the fault, a fine-grained sandstone occurs, 

 only distinguished from typical Banter by being somewhat paler. 

 Probably this is, however, a fine-grained Keuper, as at the north- 

 east end of the bank, a few yards away, and about a dozen feet 

 higher up than the fault line, is a mass, in situ, of sandstone, coarse, 

 soft, dull reddish-brown, micaceous, and containing rolled marl 

 fragments — undoubted Keuper — so that the Keuper comes right 

 down to the fault plane, or to within five or six feet of it. 



We can rouglily calculate the throw of the fault thus : At the 

 cave in Mount Segg [see Sketch Map] the dip is 9° at right angles 

 to the scarp. At the Bunter Quarry, on the Bissell Hill scarp, the 

 dip is about 13° at right angles to the scarp. We may assume the 

 dip to remain fairly constant for the distance between the two scarps. 

 Taking its average value as 11°, which is equivalent to a rise of 

 1 in 5, and the rectangular distance between the I'espective boundary 

 lines as 2200 feet, we have in 2200 feet a rise of 440 feet, i.e. the 

 base of the Keuper at Bissell Hill, had there been no fault, would 

 have been 440 feet higher than at Mount Segg. But we find that it 

 is actually at about the same altitude, viz. 300 feet above sea-level. 

 There must, therefore, have been a downthrow to the north-west of 

 about 440 feet, and without this the Keuper would have been long 

 since removed. 



The fault is represented in the Sketch Map as a single line of 

 fracture dying out in each direction. Whether this is really the 

 case is open to question, as there is no evidence to be obtained. It 

 may continue, perhaps, in a south-westerly direction to merge into 

 a fault which passes near the village of Churchill,^ each having 

 a downthrow to the west. 



Conclusion. — We have seen that the top beds of Bissell Hill agree 

 perfectly with the Keuper Beds [f6] of the main escarpment, and 

 that the lower beds of each agree in being undoubted Upper 

 Bunter [f 3]. The Keuper capping is isolated from the main mass 

 and is therefore an outlier, and has been produced by the downthrow 

 of a strike fault parallel to the two escarpments. 



At A and B [on the Sketch Map] are scattered numerous rock 

 fragments, chiefly derived from the Clent district to the north-east. 



isTOTiCES oip nycEJviionas. 



Note on a Paper on "Eozoonal Strttcture of the Ejected 

 Blocks of Monte Somjia." 



IN a letter to the Editor, Sir W. Dawson, of Montreal,, has com- 

 municated his reasons for the belief that the appearances 

 described lately by Dr. Jqhnston-Lavis and Dr. J. W. Gregory, in 

 their paper on " Eozoonal StiHicture of the Ejected Blocks of Monte 

 Somma," * have no relation to Eozoon Canadense, either in mode of 

 occurrence and mineral character or in microscopic structure. He 



1 See Geol. Survey Map, Sheet 54 N.W. 



2 Scientif. Trans. Eoy. Dublin Society, series ii, vol. v, part vii, pp. 259-277, 

 five plates ; October, 1894:. 



