221 



structure and conchoidal fracture ; this band measures 14ft. in thickness, 

 and at its upper part, immediately beneath a line of dark and rusty shale, 

 one inch in thickness, (at * in section, base of No. 4,) the remains of fish 

 (coprolites, teeth, scales) were found ; one of the few in.stances of organic 

 remains occuiTing below the black shales of the Contorta series having 

 here been determined. Dark shales, comprising bed No. 4, and 1 ft. Sin. 

 in thickness, comjjlete the lower marly series. The 16 feet of red, gi"ey, 

 and white alternating Marls, &c., (No. 1 in section,) are of interest only 

 to the stratigraphical or physical Geologist, and out of the 35 feet that 

 occur between tide mark and the first fish bed, No. 5, should be classed 

 with the Keuper ; but the beds, Nos. 2, 3, 4, hitherto considered as 

 belonging to the New Red series, I have no hesitation in placing as the 

 base of the Rhsetic seiies at Westbury. Collateral evidence, and 

 equivalent beds, as determined through correlation with other sections, 

 with the occurrence of fish and other remains in these pale grey Marls, 

 fully warranting our throwing the line lower, or farther back in time: 

 the evidence to establish this is seen in all the sections I know, when 

 carefully worked out ; and in tliis country these upper Marls are the 

 equivalents of the Tiibigen Sandstones and marls of Quenstedt. 



We now commence the true Contorta Zone or Black Shale series at 

 Westbury Cliflf, those beds knO>\T3 to older Geologists as the " Bone 

 Beds,"* and so well seen here, as well as at Aust Passage and Coombe 

 Hill, (fee. A marked change occurs at No. 5, the first hard bed in the 

 section, and also the first in which may be found an assemblage of fossils, 

 continuously or universally distributed through the sandy matrix. It is 

 indeed, the^;??-*^ Bone bed, and in which occur the scales of Gyrolepis 

 Albertii, Ag., teeth of Saurichthys apicalis, Ag., small coprolites, and 

 fragments of the enamelled teeth of Sargodon tomicus, Plein., with 

 casts or moulds also olPullastra arenicola, Strickl. : and Avicula contorta, 

 Portl., — their first apjjearance in the beds of this section. This Sandstone 

 bed is divided into two portions, the uppermost layer being 3 inches in 

 thickness, and the lower 2 inches ; and in this lower jjart it is that the 

 fish remains occur. The entii-e bed is a micaceous Sandstone, in places 

 pyritic, and is couspicuous in the clifi" as the lowest of the two Pullastra 

 Sandstones known to most local observers. This first fish bed (No. d) 

 should be termed or known as the " Micaceous Bone bed." 



Resting upon the rather uneven surface of this Sandstone is a succes- 

 sion of dark grey fissile sulpliurous shales 1 foot 10 inches to 2 feet in 



* Schwabische Kloake of Quenstedt. 



