548 ME. E. AVILSON ON A SECTION OF 



" Tea-grecii Marls " and tlio Ui)per Rhaetic shales possess very similar 

 mineral characters. Whilst admitting the evidences of a transition 

 between grey Keuper marls and the Avicula-contorta shales in the 

 sections referred to by Mr. H. B. Woodward, I would point out 

 ihat there is no evidence that the *' Tea-green Marls " in the sections 

 where there is no upward passage are the same " Tea-green Marls " 

 as those in the sections where there is a passage. 'J'he " Tea-green 

 Marls" vary in thickness very considerably in different places. 

 When, moreover, we consider the vast difference in the development 

 of the Upper Keuper rocks in the different districts where these 

 sections occur, it seems imi)ossible to suppose that the light grey 

 marls into which the Red Marls so generally graduate upwards can 

 be strictly homotaxial in all these sections. Except for a faint 

 resemblance in colour, the mineral characters of the " Tea-green 

 Marls " are totally different from those of the Upper Rhsetic shales, 

 and the organic remains found in them are also different. I adhere 

 therefore to the view, which I have on a former occasion expressed,, 

 that, as a rule, both in the West of England and in the other parts 

 of the country Avhere these rocks occur, the " Tea-green Marls '^ 

 ought to be classed with the Keuper, with which they are always 

 stratigraphieally so closely linked *. 



Most of the more characteristic invertebrate fossils of the British 

 Rha)tic Beds are found at Pylle Hill, together with a few which are 

 new to this country, and some of these possibly also to science. 



Vertebrate remains are comparatively scarce. There is no true 

 " Bone bed " as at Aust Cliff, but at the base of the Avicula-contorta 

 shales there is a very thin and irregular seam of pyritic grit con- 

 taining the teeth, scales, and coprolites of fishes. Bed g, a compact 

 blue shelly limestone near the top of the Paper Shales, yields, in 

 addition to the commoner Rhtetic bivalves, a number "of small 

 gasteropods, mostly belonging to the genus ActcFonina. The occur- 

 rence of the tiny brittle-star Opliiolepis Damesii in bed /" is interest- 

 ing, as it has not hitherto been recorded from the Bristol district. 



In the Upper Rhsetic series the l-hicl?: bed of limestone i yields 

 innumerable remains of the little freshwater plant Naiadita^ de- 

 scribed by the Rev. P. B. Brodie in his classic work on Fossil 

 Insects t, and by the late Prof. J. Buckman, in the pages of the 

 Quarterly Journal t, as having been derived from the " Lias '' of 

 Bristol. Associated with these plants are innumerable tests of 

 minute ostracoda, which Prof. T. Rupert Jones tells me probably 

 belong to two species of Danvinula. The succeeding bed of lime- 

 stone I also contains scattered fragments of Naiadita associated with 

 the well-known ostraood Estheria minuta, and minute ostracoda 

 similar to those found in beds i and I crowd the surfaces of the 

 laminae of the overlying shales. 



* ' The Ehaetics of Nottinghamshire,' Quart. Journ. Geol. Soc. vol. xxxviii. 

 (1882) p. 4r)l. 



t ' Fossil Insects,' p. 92 et seq. 



I ' On some Fossil Plants from the Lower Lias,' Quart. Journ. Geol. Soc. 

 vol. vi. (1850) pp. 414-415, figs. 2, 3, 4 ; see also W. W. Stoddart, Proc. 

 Bristol Nat. Soc. n. s. vol. ii. (1879) p. 280. 



