Vol. 67.] ASSOCIATED KOCKS OF NORTH-EAST MONTGOMERYSHIRE. 419 



Saloi 



L 11 (1 1 o w. 

 800 feet + 



W e n 1 c k. 

 200 feet. 



Yr Allt Group. 



'3. Sandy flags and shales, some- 

 times calcareous. 



2. Hard thick flags, with thin 

 shale-bands and septarian 

 nodules. 



1. Thin muddy shales. 



f B. Western C Blu 

 p . < c; 

 facies. ^ b 



Blue flags, gritty, with cal- 

 careous ' concretions ' or 

 boulders. 

 rBlue flags, as a rule minutely 

 j A. Eastern ) false - bedded, with earthy 

 ^ facies. 1 mudstones and a thin lime- 



v. stone-bed. 



Valentian. 

 700 feet, 



Buttington Group 



(=Tarannon Shales). 



300 feet. 



3 Barren 

 j purpl 



shales, green and 



Upper 



Llandovery 



p 



Lower 

 Llandovery. 



r B. Western 

 facies 

 (Cloddiau 

 Gi'oup) 

 250 feet. 



A. Eastern 



facies 

 (Cefn Group) 

 50 feet. 



Powis-Castle 

 Group. 

 100 feet. 



j 2. Thick calcareous flag^ and 

 <( mudstones. 



I 1. Blue shales. 

 I 



! Tbick calcareous flags, with 

 i Pentamerus Limestone. 



C Red sandstones and conglome- 

 ■< rates, with occasional develop- 



Ashgillian ? 

 50 feet. 



Gwern-y-brain Group. 



ments of limestone. 



f Black shivery phosphatic shales, 

 with a band of black crystal- 

 line limestone near the 

 base (=Stanrocephalv.s Lime- 

 stone ?). 



1 



Caeadocian. 

 1300 feet. 



Glenkixx- 

 Haetfell 



( =DlCRANOGBAPTrS 



Shales). 



Gaerfawr Group. 

 1000 feet. 



1 1 - y - g 1 Group. 

 300 feet. 



T r i 1 b i t e - D i n g le Group. 

 1000 feet ? 



f3. Hard calcareous mudstones 

 and limestones (= Lower 

 Bala Limestone) with coarse 

 asli3 r felspathic bands ; 

 thin phosphatic ashy shales 

 at the base. 

 2. Massive grits, with bastard 

 limestones. 



1. Flags and grits, with some 

 t_ sbale-bands. 



C Sbales and flags, with some grit- 

 \ bands. 



2. Nodular mudstones and grey 



shales. 

 1. Splintery grey shales. 



