ON EXCAVATIONS IN THE PAL/EOZOIC ROCKS OF WALES, ETC. L15 



obtained from Excavation No. 30 (Sheffield Report) are of the nature 

 of tubes in the body of the sandstone. 



Excavation No. 42, West of Hill House. 



At a point close to the K of the words ' Wrekin Quartzite ' on the 

 map a few natural exposures of reck were visible on the surface. On 

 opening these up, the rock was found to be a dark-blue quartzite inter- 

 calated with yellowish sandstone, but the beds are so much fractured 

 that no definite section could be measured. The dip is nearly vertical 

 and the general strike north and south. Several trial openings between 

 Nos. 41 and 42 failed to reach solid rock. 



Excavation No. 43, near Spring, South of Robin's Tump. 

 A spring is indicated on the map (Sheffield Eeport) about 150 yards 

 south of Eobin's Tump. The Lower Comley Sandstone found on the 

 Saddle, in Excavation No. 29 (Sheffield Eeport), is traceable by surface 

 debris up to this spring, where it is succeeded southwards by indications 

 of shale. Openings made just above and south of the spring proved the 

 existence of shale, with a north and south strike and a nearly vertical 

 dip, and containing at least one band of rotten-stone, plentifully charged 

 with Orthis (Orusia) cf. lenticularis fVYahl.). 2 The shales vary a good 

 deal in hardness within a few yards and are strongly reminiscent of 

 those of Excavations Nos. 20, 21, 25, 26 (Sheffield Eeport); they may 

 therefore be assigned to the Shoot Rough Road group. 



Conclusion. 



The stratigraphical relations of the Cambrian rocks of the Comley 

 area, as they have been laid bare during the excavations carried on 

 under the auspices of the Excavation Committee, were summarised in 

 my previous Report (Sheffield, 1910). But these excavations have also 

 yielded me during their progress a large array of Cambrian fossils. 

 Most of these Trilobites have now been described and figured by myself 

 in papers read during the last two years before the Geological Society 

 of London, and the Brachiopods from the higher horizons of Shoot 

 Rough Road have been described by Dr. C. A. Matley. 3 The Hyo- 

 lithidce and Brachiopoda of the lower horizons have not yet been fully 

 determined. 



When it is borne in mind that the excavations already made deal 

 with only a small portion of the collective area occupied by the Cam- 

 brian of Shropshire, it is evident how very desirable it is for the sake of 

 British geology that the excavation work shall be continued. 



2 Dr. Matley has very kindly assisted me with this identification. 



3 See Cobbold, Q.J.O.S., vol. lxvi., 1910. pp. 19-51, plates iii. to viii., and 

 vol. lxvii. 



I 2 



