﻿Vol. 6 1.] EHiETIC KOCKS OF MONMOUTHSHIRE. 377 



5 feet below the base of the Pvhaetic beds ; they vary from 3 to 12 inches in 

 width, and can sometimes be traced for 7 or 8 yards. Among the fish [es], 

 Gyrolejpis Alberti, Ag., and Hijbodns minor, Ag., have been recognized, by 

 Mr. E. T. Newton : Sanrichthys, also, is quoted by Mr. Lee.' 1 



Mr. Horace B. Woodward 2 (as I have already mentioned) has 

 commented upon the importance of finding a bone-bed containing 

 remains of Rhaetic vertebrates in the 'Tea-Green Marls,' since, in his 

 opinion, it links the deposits in which they occur with the R-haetic. 

 The mode of formation, however, of these ramifying veins of quartz- 

 sand is obviously not that under which a continuous stratum was 

 laid down. They are certainly distributed, so far as can be seen, 

 along a definite stratigraphical horizon, but the suggestion that the 

 material accumulated in runlets in a mud-flat is not altogether 

 satisfactory, although it very nearly explains the phenomenon. 



(B) Bishton. 



To the east of Newport a considerable tract of country is com- 

 posed of Rhsetic and Lower Liassic rocks. In this area are several 

 excellent sections, which have hitherto remained undescribed. The 

 first to be noticed is at Bishton. At the northern end of the 

 village a lane leaves the Llanmartin road on the right, and leads to 

 Poolhead Cott. This lane is now frequently occupied by a stream, 

 but the steep banks afford a magnificent and accessible section of the 

 'Tea-Green Marls,' the Lower Rhsetic, and most of the component 

 beds of the Upper : the only deposits of which it is a little difficult 

 to obtain measurements being those immediately above and below 

 the EstJieria-Bed. Estheria was not recorded here, but it was 

 observed at Goldcliff, and the lithic structure of the limestone is 

 identical. 



As will be noticed from the following record, this section much 

 resembles that at Goldcliff : — 



Lower Lias. Limestones and Clays. ^ ee ^ inches. 



( 1 a. Cotham - Marble equivalent. A 



; smooth-textured limestone with 



C I bluish centre ,, 6 



h j b. Clay-parting 0^- 



§ c. Limestone, hard, crystalline 2 Fish-scales (rare). 



P3 J 2. Shales, yellowish, marly about 2 



| I 3. Limestone : Estheria-Bed. Sometimes 

 £ a creamy - yellow, smooth-textured 



|5 j limestone with bluish patches, and at 



j others a hard nodular limestone with 



I ' aborescent ' markings 4 



' v 4. Shales, greenish and yellowish, marly. 1 5 



1 Mem. Geol. Surv. 'The Geology of the South-Wales Coalfield' pt. 

 The Country around Newport, Monmouthshire ' 1899, pp. 75-76. 



2 Proc. Geol. Assoc, vol. x (1888) p. 538. 



