Vol. 62.] AN UNCONFORMITY IN THE COAL-MEASURES. 541 



sandstone-layers. In the latter also occur numerous lenticular 

 pockets of clean coal (locally known as ' scares '), and occasionally 

 of shale. These ' scares ' have a characteristic wavy outline, and, 

 although not marked in the other sketches, abound at many places 

 along the coast-section, occurring sometimes up to 6 feet above 

 the base of the Table-Rocks Sandstone. At FM 1 , and thence to 

 FM", FM 111 , FM IV , FM V , and FM VI , are several faults; not, as before, 

 in the series beneath the unconformity, but affecting the lower 

 portions of the Upper Series only. Some of these are rectilinear 

 with ordinary hades ; but three (FM IV , FM V , and FM VI ) are curvi- 

 linear and very flat-haded. All, except the fault at FM 1 , hade to 

 the south. At N the section closes with a vertical fault which 

 throws the whole of the rocks, both above and below the uncon- 

 formity. In amount its throw is small, but the fault-fissure is 

 well-marked and filled with clay or ' dowk ' (fig. 12, p. 540). 



It would seem as if the various appearances exhibited in this 

 line of section may be explained by a certain amount of differential 

 action within the beds above the unconformity, rendered possible 

 only when these are, as in the present case, no longer homogeneous, 

 but of rapidly -changing hardness and texture. Also perhaps in 

 such circumstances a certain, though small, amount of intermingling 

 of the Lower and Upper Series has taken place near the shearing- 

 plane during the general thrusting movement towards the north. 



Beyond N, the sandy beach rarely shifts sufficiently to afford 

 many glimpses of the state of things beneath it, and but little 

 information can be gleaned from the low Drift-covered cliffs. 

 Opposite the Convalescent Home, however, some remarkable 

 exposures are at times visible. These show a continuation of the 

 kind of disturbance in the Lower Series of beds, which has been 

 described as commonly occurring in them to the south of M. The 

 Mussel-Band here again furnishes the best evidence at our disposal. 

 Tnus, between the water-pipe and the drain-pipe running from the 

 Convalescent Home to the sea, the Mussel-Band is repeated three 

 times by small east-and-west faults, and a little north of this, 

 small anticlinals and isolated outcrops with curved strikes and 

 dipping in various directions are observable, but the connexion 

 between these stratigraphical details is necessarily wanting. There 

 is no evidence whatever of the unconformity north of N. 



It may be mentioned that, close to the low-water line immediately 

 to the east of the small, though sharp, disturbances just noted, the 

 strike of the thin sandstones below the Mussel- Band is normal in 

 character, that is, parallel both to the coast-line and to the strike of 

 the Table-Kocks Sandstone, which is here, however, only marked 

 by a small surface-feature, and covered by Boulder-Clay and blown 

 sand. This arrangement — faulted and folded beds west of, and 

 close to, a continuous, unbroken north-and-south outcrop — suggests 

 a strike-fault between the two areas. We have, however, failed 

 to find any good evidence of such a fault, even a small one ; 

 and the recognition of the thrusting action renders such a fault 

 unnecessary. 



Q.J.G.S. No. 247. 2o 



