PRECARBONTFEROUS ROCKS OF CHARNWOOD FOREST. / 0/ 



which is highly altered, becoming a very splintery hornstone-like 

 rock ; but the actual junction is not visible above ground. The 

 slate is dipping in the direction usual in the neighbourhood. These 

 Charnwood intrusions, except in a very few cases, do not seem to 

 disturb the dips in their vicinity. The apparent curving of the 

 planes of dip at this end, from south-west at Markfield to south at 

 Bradgate, may, however, be due to the great intrusive mass here, 

 whose area is apparently two or three square miles. 



In Bradgate Park the peculiar contortions and slickensides of the 

 beds in the Stable Quarry long ago suggested to us the probability 

 of the neighbouring syenite being intrusive ; but it was not till after 

 we had found the above junction that Mr. Hill discovered fragments, 

 showing syenite and banded slate in contact, built into the wall 

 surrounding the ruins, and picked up one beautiful contact specimen 

 a little further up towards Old-John Hill. 



About the last letter of the word Bradgate on the Map, is a small 

 patch of syenite, here rather less coarse than usual, with a large 

 mass of banded slates within five or six yards. The slate here is 

 almost a hornstone, showing a sort of rippled marking, seen in some 

 other places near the igneous rock, and a platy jointing. The 

 syenite, as usual, becomes rather more finely crystalline as it ap- 

 proaches the slate, and is in contact with the sedimentary rock, 

 though the very small portion of the junction visible is not quite 

 sufficient to determine the precise character of the latter. Micro- 

 scopic examination shows that the nature of the junction is indu- 

 bitable, and that the syenite is intrusive. 



There is therefore no doubt that the mass of syenite in Bradgate 

 Park is also intrusive ; and it is quite possible that careful search 

 within the ruins may yet detect the junction in situ. 



An outcrop of syenite, with slate on both sides of it, can be seen 

 at Groby-Park Farm. On the eastern side the two can be traced to 

 within six feet of each other. The slate is much jointed ; and the 

 syenite here and there shows the platy jointing often noticed in an 

 igneous rock parallel to its junction-surface ; but the evidence here, 

 without excavation, would not be quite conclusive. However, after 

 that obtained elsewhere, no difficulty can be felt in admitting intrusion 

 here also. At Markfield, and at Cliff Hill, no slates are seen suffi- 

 ciently near the syenite to give any information ; and the same is the 

 case at Hammercliff, though it is just possible that the plantation may 

 contain exposures which, up to this time, have escaped our notice. At 

 Bawdon Castle the syenite becomes compact, and may be seen almost 

 in contact with the breccia*. Birchwood and Bardon Hill, though 

 highly altered, contain no igneous rock. The syenite (greenstone 

 of Map) on Buck Hill is restricted to a small patch at its northern 

 end. We have no doubt that the syenite here is intrusive ; but the 

 evidence is not quite so absolutely unquestionable as at the localities 

 mentioned above. This syenite is always less coarsely and distinctly 

 crystalline than that of the more southern district. The sedimentary 

 rock here happens to be of a somewhat gritty texture ; so that there 



* We discovered this instance after the paper was read ; details of it will be 

 given in Part II. 



