756 E. HILL AND T. (i. BONNEY ON THE 



steep, almost vertical, and E.N.E. (85° and N.E., Jukes). It con- 

 sists of a series of alternating beds, some of fine-grained good slate, 

 some of a greenish ashy aggregate of pebbles and fragments of slate, 

 quartz, and felspathic materials. It is rather schistose, with a sil- 

 very lustre. Hounded grains of quartz, felspar, and a black mineral, 

 possibly hornblende, may be detected ; parts of the rock have a very 

 soapy feeling ; and altogether it has the aspect of a volcanic ash, 

 mingled with other detrital materials waterworn and greatly com- 

 pressed. 



About half a mile further, the road ascends a hill, not named on 

 the map, but called Nanpanton in the neighbourhood. Here there 

 is a fine exposure of what will be called throughout this paper banded 

 slates. As this is the most common rock of the Forest, we may describe 

 it here once for all. It is an alternating series of finer and coarser 

 sedimentary materials — the former generally bluish or green, some- 

 times whitish or pink, and felspathic or argillaceous, the latter gene- 

 rally quartzose. The finer often weathers white for some distance 

 inside. It is not often perfectly cleaved, but is generally very hard, 

 so indurated sometimes as to almost resemble a porcellanite or horn- 

 stone ; its surface will sometimes turn the edge of a knife. The 

 strike in this part of the Forest is rendered conspicuous by differences 

 of colour, while in other parts it is only made visible by unequal 

 weathering of the different bands. Dip is, of course, always obvious 

 and easily measured. These slates are only contorted in one or two 

 localities ; but the strike and dip frequently change a little within a 

 very short space. AVhile the series, as a whole, is remarkably 

 distinct, there is the greatest difficulty in tracing any one bed from 

 point to point ; nor are we aware that, before this paper, the attempt 

 has ever been made. 



At the top of the hill is a coarser bed of a greenish slaty ash, 

 barely, if at all, showing stratification. 



The small patch on the crest of the hill, coloured greenstone on 

 the map, is correctly indicated. It is more strictly a syenite, like 

 that of Garendon, which will be described hereafter ; some ashy grits 

 show out near to it. The exposure south-east of Longcliff consists 

 of banded slates, with the strike but slightly indicated. That of 

 Kidney Plantation we have not examined ; and beyond it, at Lubcloud, 

 we are on the other side of the anticlinal. 



The rocks exposed at Longcliff are mainly slightly banded slates, 

 intermingled Avith coarse grit bands. About the middle of the ridge 

 there is a bed of a coarse lumpy ash, with some included fragments 

 of slate. 



2. Starting again south of this section from the Buck-Hill woods, 

 there is an exposure (at the word " out") which we have not exa- 

 mined. The patch, coloured " greenstone " on the Survey Map, 

 consists almost entirely of banded slates, some of the most distinct 

 and characteristic examples of these rocks in the district. There is, 

 however, at the north extremity, as Jukes says, " a small quarry of 

 a true close-grained greenstone " similar to that above-mentioned. 



Low down in the series, on the S.W. side of a singularly steep and 



