]»artlij (• vHiMiMiKinM s i.i mkstonk of s. walks coai.fikld. Ill 



Minliola phase at the l>aso of L\.' OM (.Quarry at the CaHtt-ll- 

 y-Mynach Arm«. near Croftau (Glam. 42 NW X20). 



Feet tnr)n-s. 



7. ('aleite-nnjdston,' : lunch like that of (5) seen for 2 <• 



<>. Oolitic limestone: dark ^'ivy to black. Athyrids of 



Seniinuloifl form fairly numerous f. 



-'». Calcite-mudstones : dark jrroy to black, weathering to 

 a white skin. Tliiekly-bedded. with partings of black 



sliale and jdaty calcite-njudstone 8 < ' 



Holomite: thinly-bedded, and very fine-jrrained (in thin 

 section under the microscope, irregular i)atches of ex- 

 ceedingly fine-grained dolomite enclosed by dolomite of 



less line grain) 2 o 



'■ Limestone- V) r e c c i a : fragments of ck )lite and of calcite- 

 mudstone, similar in character to the noilules of (1); 

 nnitrix of tine-gniined grey limestone. The fragments 



more numerous in the lower than in the upper part 1 *> 



■-. Hed marl 2 



' Hubbly limestone and red marl, loosely coherent, 

 '^he limest(me-no<lule8 are rounded fragments of (n) dark 

 oolite, such as occurs in the underlying Cauinia Oolite, 

 and (b) dark calcite-mudstone, such as forms (5) and (7). 

 sometimes structureless, scmietimes exhibiting wavy or 

 contorted lamination. The re«l marly matrix is formed 

 largely «jf ooliths. which were probably derived from 

 fragments of oolite by gentle attrition. (Resting sharply 

 upon, and filling up ine.iUiiHties in tin' -iiitnc- i.t the 

 CVr/M/n'rt Oolite) 2 



Total thickness of. \/oWH-/a phase seen .16 2 



riiis iU'Volo|jiiu'nt ot" the ('. Modiohr j)]iase resembles very clo.sely 

 tiiat in tlie eastern distriet of (rower, «leseri))e(l bv Mr. E. E. L. 

 I)ixon.' 



10, 11. A: 12. Stjindard I iniest ones.- The «,'eneral lithol.i^'V 

 liHs been de.seribed in the table on p. M(). The fainial eharacter- 

 isties may be delinetl by means of a tabnlar list of fossils, sn))i)le- 

 inented by notes on salient featnres. 



A hnxe element of fannal eontinnity thronL,d»out the .series is 

 evident from the table ( p. I 12). On the one hand, however, several 

 features of (ironp 10 serve to difl'erentiate this Lrronp fnim the 

 rest of the series, and to eharaeterize it as Lower V : sueh are 

 the abundance of Si'ininiila ef. amhlifim, the eom|):ir.itive seareitv 

 of Prothirtim cornff//ffn-/tri/u'sjfhrr/rtfs and Cifoflinphiflhim 0, and 

 the absence or nirity of ('arrinoithifUmii and IJthnsfrntinii.- On 

 the other hand. Lrroui)s 1 1 an<l 12 rej>resent r]»|Mr (' and S , and 

 totrether constitute Hori/.on r as .inende»l by Vauijhan,"^ well 



' (tower paper, pji. 4H.5 Si\. 



' Compare the Hurrington-Cond>e section. Mendips ; A. Vanghan. K^. .1. (i. S. 

 vol. Ixvii (H»ll) pp. :U5S m. 



^ ■ In the Soiith-West^'ni Province. Horizon T includes Upper C . and S,,that is, 

 from the maximum of (^V(f//i'»/)/i7//i/»i ip to the incoming of ('//Wr'H<K-or/»o;Mina.' 

 A. Vanghan. Q. J. (J. S. vol. Ixxi (191.'> I CO p. IS. The base of Horizon T, 

 and. therefore, the boundary between our groups 1(» and 11. is the division- 

 line between Toumaisian and Vis.an adopted by Del. pine and Vanghan: 

 i/mV/., f«)lding tjible facing |». '.VI. 



m2 



