Vol. 67.] SALOPIAN ROCKS OF CAUTLEY AXD RAYENSTOXEDALE. 217 



We have recognized the following zones in the Salopian rocks of 

 Cautley and Ravenstonedale : — 



Tr.vr.., t.,^ , ,., f Do Zone of Mmoqraptus leintwardinensis Hopk. 



JjOWEB JjUDT.OW. n J 7 e tut * ■! • t> 



[ D L Zone ot Monograptus nilssom Ban-. 



Phacops-obtusicaudatus Bed. 

 fCj Zone of Cyrtograptus lundgreni Tullb. 

 Whntopk ' Zone °^ Cyrtograptus rigidus Tullb. 



J a Zone of Monograptus riccartonensis Lapw. 

 [C| Zone of Cyrtograptus murchisoni Ca-rr. 



II. The Wexlock Beds. 



The Wenlock Series is well exposed in three distinct areas in 

 the Cautley district : namely, in the neighbourhood of the Rawthey, 

 Wandale Hill, and Harter Fell. The rocks present three fairly 

 distinct lithological types : (1) blue nags, (2) yellow sandy beds, 

 and (3) red flags and grits ; but in each case the same zones occur. 

 The whole thickness of the Wenlock Series exposed in this area 

 does not exceed 900 feet. 



It has been possible to work out the approximate thickness of 

 the zones in the Rawthey area as follows : 



T/tickness in feet. 



Zone of Cyrtograptus Umdgren i 300 to 400 



Zone of Cyrtograptus rigidus 178 



Zone of Mon t.graptus riccartonensis 160 



Zone of Cyrtograptus on urchison i 100 



(a) The Rawthey and. the Western Slope of Bluecaster. 



We have obtained our most complete sections through the 

 Wenlock Series in the neighbourhood of the Rawthey. We therefore 

 propose to describe the "Wenlock Beds of this area in detail, and 

 to give only general descriptions of the confirmatory sections 

 elsewhere. Xear the Rawthey each zone is exposed, and a con- 

 formable succession is obtained downwards into the Browgill Beds, 

 and upwards into the Phacops-obtusicaudatus Bed, which here, as 

 elsewhere in the Lake District, separates the strata of Wenlock 

 from those of Ludlow age. 1 



The Wenlock Series occupies a narrow strip of country, from 

 Birks Field Beck north-eastwards to the mouth of Wandale Beck. 

 There is uniformity in the character of the beds throughout this 

 area. They are massive jointed flags, finely banded, blue-grey 

 when unweathered, and becoming brown on exposure to weathering 

 agencies. 



As has been noticed elsewhere, 2 the argillaceous character of the 

 rocks has so greatly favoured cleavage that it is always difficult 

 to obtain a good surface along the bedding-planes ; even when such 



1 J. E. Marr, Geol. Mag. dec. 3. vol. ix (1892J p. 5 K). 



8 ' Geologv of the Country around Mallerstang ' (Expl. of Quarter Sheet 97 

 N.W.) Menu Geol. Suit. 1891, p. 34. 



