Coal-Seams of Vaji Diemen's Land. 119 



consisting chiefly of sandstones, with a few beds of black and 

 grey shales towards the upper part, but in which no seams 

 of coal occur. 



About four hundred yards below the junction of the "Back 

 Elver" with the Derwent, and nearly opposite the Falls, a 

 considerable fault shows itself in an almost perpendicular 

 cliff on the south bank of the river, where what would appear 

 to be the lowest sandstone of the carboniferous series is 

 brought in contact with a set of beds composed of a very 

 hard, white, compact, and regularly bedded claystone rock, 

 with occasional thin beds or partings of dark blue and grey 

 micaceous and arenaceous shales. 



On the weathered faces of these beds numerous large 

 cavities occur, which are often coated with efflorescences of 

 sulphate of magnesia and alum in small crystals. In some 

 places the beds are conglomerate, and contain pebbles of 

 quartz, granite, quartz rock, and a very hard dark siliceous 

 rock. 



Up the "Back Eiver," and in the hill opposite the Govern- 

 ment Cottage at New Norfolk, where these beds are well 

 exposed in bold, nearly vertical, cliffs, they are distinctly 

 seen passing conformably under the carboniferous sandstone, 

 the whole dipping about (W. 10° S.) 5° to 6°. 



The total thickness of beds exposed in this hill cannot be 

 much less than 700 feet, or about 400 feet of clay-rock and 

 300 feet of sandstone — the latter forming the capping of 

 the hill, and being in all probability the same beds which a 

 mile and a half higher up the river, at the Falls, are thrown 

 against the former by the fault before mentioned. 



In following the Hobart Town road from New Norfolk, 

 the only sections exposed for about four miles consist of 

 alternations of basalt, and recent river deposits of sand and 

 gravel resting on the former. 



