114 Baden Powell — Igneous Rocks of Charnwood Forest. 



by contact with the igneous rock. If so, this locality exhibits a true 

 junction of the slate and igneous rock, not hitherto detected. 



Basaltic Dylces. — Mr. Jukes, in his Memoir (1842), has circum- 

 stantially described two basaltic dykes in the neighbourhood of 

 Mount Sorrel. Neither of these can now be traced as described. 



The first is mentioned in the quarry near the Buddon Wood, on the 

 opposite side of the road. The ground plan of this pit is annexed (Fig.2). 

 It is situated in the slope of a hill, and opens level with the ground 

 at the south end. The rock is everywhere syenite, like Mount Sorrel, 

 except at the points marked a, h, c, where there rise up, from the 

 floor of the pit, two small projections (a, 6), of a dark brown, but 

 not very hard, rock, much split and shattered, perhaps two or three 

 feet in height and breadth, and extending six or eight feet in length ; 

 and at c a small buttress of the same rock projects from the wall, 

 but no termination of it can be traced on the other side. The mass 

 of the dyke has, doubtless, been quarried away since Mr. Jukes 

 wrote. 



The second dyke is described as existing in Simpson's pit, near 

 the S.W. corner of Mount Sorrel Common. This small pit is not 

 now worked. I found it (1859) filled up partly with rubble, partly 

 with syenite, broken, and worked for paving. In this I could find no 

 specimen of basalt. And, in carefully examining all the rock which 

 appears round the margin, could detect no appearance of the termi- 

 nations of any dyke. It must, probably, have been all quarried 

 away like the first. Lest any mistake as to the locality should have 

 been committed, I carefully examined every pit, or appearance of 

 rock, in the neighbourhood, but could detect nothing like a basaltic 

 dyke. 



At quite the opposite side of the forest, near Markfield, in a pit at 

 the cross roads, another dyke has been pointed out by Mr. Jukes, 

 which is remarkable from the conformable manner in which the 

 altered slate is superimposed on it. I found it to consist of an 

 intensely hard, compact, dark grey mass, presenting, when exposed, 

 a rounded surface, to which the slate conforms.^ 



Anticlinal Axis. — The anticlinal axis of the slate district was 

 originally traced by Professors Sedgwick, Whewell, and Airy in 

 1833, in a line extending from near Whitehorse Wood at the N.W., 

 to somewhere near Swithland Wood at the S.E. The more detailed 

 examinations of the Government Survey have confirmed this general 

 direction, but show the necessity for some modifications in its details. 

 But the general resulting character of the elevation has not been 

 clearly described. 



In its northern portion the anticlinal axis is clearly defined running 

 in nearly a straight line, for the most part in a continuous valley, 

 the hills on each side having opposing dips from the neighbourhoo. 

 of Whitehorse Wood, in a S.E. direction as far as to near Bandon 



1 In the extensive syenite quarry at Markfield, a vein of compact calcite occurs of 

 considerable extent ; it has a red or pink tinge, and possesses throughout the well- 

 defined rhombic cleavage. It has been proposed to use this for economical pur- 

 poses, owing to the extent of the vein and its pure character. 



