UPPER LIAS. 277 



a single band of limestone, known as the Fish and Insect Bed. 



Hence the beds are divided as follows : — 



ft. in. 



Marl a.nd limestone v/'\ih Ammo)t/yt?s comMiim's 6 o 



Irregular whitish hmestone and clay with A. serpentinus 2 to 6 feet 



Fish and Insect Beds I 6 



Transition-bed with A. actitus. (See p. 273.) 

 Rock-bed of Middle Lias 



In Rutlandshire, etc., the Upper Lias presents a thickness 

 of about 200 feet, and is divided as follows by Prof. Judd : — 



Leda ovum Beds. — Clays with septaria and many specimens of L. ovitm, 



A. bifrons, A. communis, etc. 



Dark blue clays with pyrites and jet (fossils rare). 

 Aminonites communis Beds. — Clays with A. communis, A. aititulatus, etc. 

 Ammonites serpentinus Beds. — Clays with layers and nodules of limestone, 



A. serpentinus, A.falcifer, A. concavus, A. radians, etc. 

 Paper-shales with Fish and Insect Limestones. 



Prof. Judd suggested the name Dumbleton Series for the 

 Paper-shales, from the village of Dumbleton between Cheltenham 

 and Evesham, at which locality the beds were first studied by the 

 Rev. P. B. Brodie.' Remains of Dragon-flies, Libelliila, have been 

 obtained from this locality. The Upper Lias (20 feet) is shown in 

 brickyards near the railway-station at Market Harborough. 



In Lincolnshire the Upper Lias has been divided as follows by 

 Mr. W. D. Carr:^— 



Beds with Ammonites bifrons. Paper-shales, with few fossils. 

 ,, ,, A. communis. Clay with septaria, many fossils 



{Nuciila Hammeri Beds). 

 ( Clay with limestone and gritty 

 ,, ,, A, serpentinus. \ bands. Z^t'/t'w/zzVd'j- very abundant. 



( Pyritous clay with limestone bands. 



The beds may be studied as Swan's brickyard on the north cliff, 

 near Lincoln (see Fig. 42), at Bracebridge (Best's brickyard, upper 

 pit), and at Navenby. 7'rigonia pukhcUa is a noteworthy fossil in 

 the beds with NuciiIa Hainmcri. The Upper Lias is about 70 feet 

 in thickness. 



The Upper Lias of Yorkshire varies in thickness from 200 feet 

 on the coast, to 50 feet and less in some of the southern Cleveland 

 Hills. It is exposed in the clifts of Robin Hood Bay, near Whitby, 

 and Rockclifif. Three lithological divisions have been recognized, 

 and these broadly speaking are characterized by species of 

 Ammonites : — 



Zones of A. communis ] Alum Shale. Shales with nodules (cement-stone 

 and ^. bifrons. ] beds), 1 10 feet. 



,, ,, A. serpentinus. Jet-rock series. Shale with jet and pyrites, 50 to 



60 feet. 

 ,, ,, A. annulatus. Grey shale. Hard and compact grey micaceous 

 sandy shale, 30 feet. 



^ Geol. of Rutland, etc. p. 79. See also Buckman, Proc. G. S. iv. 211. 

 ^ G. Mag. 1883, p, 164; P. Geol. Assoc, viii. 3S3. 



