ruddy hue or is smoky. These micaceous beds constitute a lar^e 

 proportion of the palaeozoic rocks of the Island, and can be 

 followed along the slopes of the surrounding hills and far inland. 

 In Christmas Cove (Boat Harbour), and following the beach 

 for a considerable distance in a westerly direction, is a very re- 

 markable conglomerate bed. It difters from the most of beds of 

 this character in that the stones, which range upwards in size to 

 ten or twelve inches, being set without arrangement in a matrix 

 of fine deposit. The ground mass is finely micaceou.s, flakey, 

 and with its included pebbles, greatly sheared. Professor Tate, 

 in the article already referred to, mentions this bed, and states 

 that the included pebbles were angular and subangular. So far 

 as my observation went the pebbles were uniformly rounded and 

 consisted mainly of quartz, quartzites, and granites, many of 

 them fractured or sheared under pressure. On the west side of 

 the township a series of these conglomerate beds occur close 

 together, having an aggregate thickness of about 27 feet. About 

 the centre of the series is a well-defined bed, three to four feet 

 in thickness, which although schistose when split, has the 

 appearance of having been laid down as an unstratitied deposit. 

 In some respects it has the appearance of a glacial bed, and 

 presents many points of resemblance to the supposed old 

 palaeozoic till bed of the mainland, as it occurs in the 

 metamorphosed area of Barossa, Balhannah, and Inman \^alley. 



Igneous Dykes. 



About the centre of Antechamber Bay the sea cliffs are com- 

 posed of the locally characteristic dark-colored, fine-grained mica 

 schists, having a strike E.N.R. and W.S.W., dipping southerly, 

 at 80^. Above this rocky cliff Mr. Nathaniel Simpson has his 

 homestead, which is built upon an igneous dyke that runs some- 

 what irregularly east and west for nearly a mile in length, but is 

 not always apparent at the surface. Although within less than 

 a hundred paces from the sea cliff, the dyke is not seen in the 

 face of the cliff, having evidently died out in this short distance. 

 It has the features of a close-grained diabase (aphanite), but has 

 not received petrological examination. Some of the contact rock 

 (which is normally a fine-gr lined biotite schist) is converted into 

 amphibole schist, with the structure of " tadpole " rock. 



Mr. H. Y. L. Brown (Report, 1898) mentions a dolerite dyke 

 as occurring at Cuttle Fish Bay, which I was unable to visit, but 

 at the homestead of Mr. Tretheway, a little to the north of Cuttle 

 Fish Bay, there is a considerable exposure of an igneous neck or 

 dyke, in the form of a knoll. The rock is very fine grained, 

 carrying gas cavities. The amygdaloids filling these cavities are 

 about the size of pins' heads, or a little larger, and are formed of 



