54 DR. W. D. LANG ON THE STRATIGRAPHY [vol. lxxix T 



Table Ledge is almost a tabular limestone ; but the best examples 

 are the typical limestones of the Blue Lias beloAv. A tabular 

 limestone may become lenticular or even nodular when followed 

 laterally. The JBj'rc7»-tabular (76 a) is a lenticular or semi- 

 nodular tabular. 



(7) L en tides and nodules. — -Lenticular and spherical 

 masses of calcareous marl or impure limestone, generally showing 

 bedding-planes. In the marls thej usually pass by more or less- 

 rapid gradations into the surrounding marl ; in the paper-shales 

 they are generally separated from the surrounding shales by a 

 jacket of beef. The Brooki Bed (74 d) is a prominent exception 

 to the last statement. 



(8) Septarian nodules. — Nodules showing wide radial and 

 concentric cracks, the sides of which are lined with crystalline 

 calcite. 



(9) Friable marl. — Impure blackish marl of a granular 

 texture, hardly showing bedding, and breaking easily, crurnblingly, 

 and ' short,' much as shortbread does. 



(10) Putty -marl. — Streaks, lenticles, and small nodules of 

 very pale yellowish or pinkish marl, generally associated with 

 friable marl, but sometimes Avith conchoidal marl. 



(11) Short-rock. — An intimate mixture of coarse cone-in- 

 cone beef and friable marl. 



(12) Besides the rock-forms already enumerated, sulphide of 

 iron occurs freely in the clays, generally in flat masses along 

 bedding-planes, often on the upper and lower surfaces of a beef- 

 seam, when it is generally much decomposed. Large clots of iron- 

 sulphide occur in places on 76 a, the BircJii-t&bul&r. Calcite 

 occurs in veins in the limestones. Selenite has already been 

 mentioned ; and barytes l is found in little, flat, circular discs with 

 radial structure, in the marls of 71 e (see p. 88). Finally, hydro- 

 hsernatite l occurs, infilling the suture-line of a specimen of 

 Paramiocercts alcinoe (Reynes), picked up in 1914 at the cliff- 

 foot beneath the remains of the burning cliff of 1908. 



(C) General Description. 



Lithically, the Shales-with-Beef fall into two divisions. The 

 upper division, some 30 feet thick, consists of paper-shales, is of a 

 brown rather than blue colour, and has more numerous beef-seams 

 than the lower division. Lenticles and nodules often have a jacket 

 of beef. The lenticular (74 d) Brooki Bed, however, although 

 occurring in the upper division, has no beef associated with it. 

 The paper-shales are capped by the Birchi Bed. This is a double 

 limestone, the upper being more tabular than nodular, and the 



1 Determined by Mr. W. Campbell Smith, M.C., Sec.G.S. 



