ThomsOjV. — Geology of Middle Clarence and Ure Vrdlci/s. 313 



jasperoid quartz are common. Granites and porphyries are only occa- 

 sional Iv seen, while dark crystalline rocks appear to be absent. No schist 

 or limestone pebbles were observed. The conglomerates were not followed 

 along their outcro]). They cross the Ouse Stream about a Cfuartcr of a mile 

 below the junction of the Wharf as a narrow band of pelWjly mudstone. 

 only 5-10 ft. thick. As already mentioned, there are two thick bands of 

 conglomerate farther down the Ouse which may possibly be Clarentian. 



The Wharf mudstones form both banks of the Wharf Stream between 

 the gorge and the crossing of the pack-track, above which the strike 

 becomes more easterly, and the beds continue into the upper Wharf. 

 The rocks are mainly dark micaceous mudstones without many con- 

 cretions, and near the junction of the tributary above mentioned yield 

 finelv-preserved specimens of Belemnites superstes Hector. Near the cross- 

 ing of the pack-track sandy beds are crowded with the shells of a large 

 depressed Inoceramus, and lower down the creek the mudstones contain 

 Aacellina euglypha and Belemnites superstes. No observations of strike 

 and dip were made, except that in one place on the left side there is a 

 reversal of dip. In the upper Wharf, what are presumably the Wharf 

 beds consist jiredominatingly of mudstones containing large Inocerami, 

 with occasional bands of harder sandstone, forming waterfalls, and thin 

 bands of pebbly mudstone. The beds are thrown into a series of folds, 

 so that a clear section was not observed. The mudstones, however, are 

 very thick. The Wharf beds were again observed in the Ouse, about 

 200 yards below the junction of the W^harf, in a large cliff on the right- 

 hand side consisting of thin-bedded sandstones and mudstones. The sand- 

 stones contain coaly plant-remains, and one block with shell-fragments was 

 obtained, which contained a plicate ostreid shell, part of the dorsal valve of 

 a Terebratellid (the only brachiopod yet obtained from the Clarentian), and 

 a small piece of the test and some minute spines of an echinoid. A con- 

 cretion picked up at this point contained a gasteropod and a Dentalium, 

 and is in the hands of Professor Wilckens, of Jena, for identification. 



Still farther down the Ouse, the lowest Wharf beds consist of hard 

 mudstones crowded with a large flat Inoceramus, and are the cause of 

 small waterfalls on tributaries coming in on each side {of. Cotton, 1913, 

 fig. 14). No specimens suitable for identification could be extracted, but 

 pieces 9 in. in length were obtained, and the whole shell must be over 1 ft. 

 in length. 



McKay's description of the Wharf beds is as follows : " The lowest 

 rocks, as conglomerates, are rather suddenly succeeded by black slaty, 

 marly beds, containing concretions of cone-in-cone limestone, and sandstone 

 bars full of Inoceramus, and here and there a belemnite and other fossils 

 characteristic of the Amuri series." 



The Wharf Gorge sandstones and mudstones occupy a width of about 

 a quarter of a mile in the Wharf Gorge, which crosses them transversely 

 to the strike, and in the lower part of the Cover Stream. The rocks are 

 dominantly sandstones, in beds 6 ft. thick below and 3 ft. above, and 

 are parted by thin beds of mudstone. The sandstones in the upper j)art are 

 fissile and slightly micaceous, and contain poorly preserved plant-remains, 

 principally fossil wood, and occasionally the cast of a belemnite. The 

 strike in the lower end of the gorge is E. 10° S., dip 63° to the north. 

 The Wharf Gorge beds extends in an east-north-east direction into the ridge 

 between the Wharf and Cover Streams, but are not there well exposed 

 for study. Where they cross the Ouse the sandstones are not so well 



