Vol/ 69.] PALiEOZOIC ROCKS OF THE CATJTLEY DISTRICT. 9 



Below the wood there is a short interval with no exposure, and 

 then the Stockdale Shales are seen. The interval seems too small 

 to allow of a full development of the Ashgill Shales, and there is 

 probably a fault at the base of the Silurian strata. 



Another development of Ashgillian rocks is found in this dome 

 in Oddgill, a tributary of Wandale Beck north of Murthwaite. 

 The beds here are separated from those last described by a fault, as 

 'noted in the Geological Survey Memoir. 



The lower part of Wandale seems to be in Caradocian strata, but 

 no fossils have been tound. The first fossils met with were in rocks 

 developed in Wandale Beck, 75 yards below the mouth of Oddgill. 

 These are of the same nature as those exposed in Backside Beck and 

 the Rawthey, and yielded : — 



Dicellograptus anceps. 

 Orthograptus truncatus Tar. abbre- 

 viatus. 



Trimicleus. 

 Phacops robertsi. 

 Liiigula. 



These deposits belong to the beds below the volcanic group. At 

 the mouth of Oddgill, as noted in the Survey Memoir, the contempo- 

 raneous volcanic group is seen, and higher beds are observed in 

 passing up this gill. These have the lithological characters of the 

 beds above the volcanic group, but we obtained no fossils from 

 them. They occur in the wooded portion of the gill, where they 

 are broken through by a large felsite sill, and continue upwards on 

 to the moorland. Where a little stream enters Oddgill from the 

 north, the mucronatus band at the top of the Staurocephalus Beds is 

 seen, having the same characters as at Watley Gill. It yielded : — 



Cheiriorus. 



Hem ioosmUcs sq uamosus. 

 Echinosphmrites araclmoidcus (1). 

 Turrilepas. 



Phacops mucronatus. 



Phacops (Acaste) apiculatus Salt. 



Above these beds, in the little tributary, is a poor exposure of 

 leaden-blue shales, which are almost certainly Ashgill Shales. 

 Beyond this, the section is covered by drift. 



The south-eastern dome. — In this dome important sections 

 are seen in Taythes Gill and its tributaries. The lower part of the 

 gill (known as Ecker Seeker Beck) certainly contains Ashgillian 

 rocks; but, before entering the moorland, Caradocian Beds are seen. 

 These occupy the core of the dome. The accompanying sketch-plan 

 (fig. 2, p. 10) of that part of Taythes Gill and its tributaries which 

 lies around Taythes House shows the relationship of the Caradocian 

 and Ashgillian strata. On the right bank of the gill, just opposite 

 the bridge leading to Taythes House, are weathered Galymene Beds 

 containing abundantly the index-fossil, farther down stream is a 

 thick sill of felsite, and immediately below this are unctuous grey 

 shales and limestones with Phacops robertsi. There is not room for 

 more than a few feet of strata between the highest beds with Oaly- 

 ■mene and the lowest Ph.-robertsi Beds ; and so here we are able to 

 draw a fairly sharp line between the Caradocian and the Ashgillian. 



