LOWER LIAS. 263 



A. Biicklandi, and large specimens of this fossil, and also of A. CJiarmassei (a 

 form allied to A. angulahis), may be obtained. These beds contain many large 

 ioxms oi Lima gigaiitea, 2i\.i,a Khynchonella variabilis, Gryphaa incurva, etc. The 

 stone is known as the ' Blue Lias ' by the quarrymen, and is largely used for 

 making cement, etc. The same series of limestones is repeated in the Church 

 Cliffs to the east of Lyme Regis, and thence we reach higher and higher beds as 

 we travel eastwards. A little distance above the main mass of the limestones, 

 there is a conspicuous pale-grey band of hard marly limestone, known as the 

 'Table Ledge,' and which descends to the beach at the foot of Black Yen. 

 This limestone contains Rhynchonella variabilis, etc., and is included by 

 Dr. Wright in the zone of Auinwnites Turneri. The dark clays and 

 shales which form the lower portion of Black Van include the zones of 

 Amnionitcs obtusus and A. oxymitus, of which fine examples may be 

 obtained. In the former zone A. Brooki, A. Birchii, A. stcllaris and other 

 species occur, generally at particular horizons well known to the local dealers 

 and collectors. A. planicosta and small specimens of A. obtusus occur some- 

 times so abundantly in bands of limestone as to form a kind of Ammonite-marble, 

 blocks of which may be picked up on the beach. Specimens of A. Birchii at 

 times are found with the chambers lined with calc-spar, and are known as 

 ' Tortoise-ammonites.' Fine specimens of Extracriiius Bruireus, generally coated 

 with or partly replaced by iron-pyrites, are met with in the zone of ^. obtusus. A 

 variety of ^. oxyuotus, termed A. Lymensis, occurs also at Black Ven. Specimens 

 of ^. subplanicosta {A. Carusensis), A. trivialis, etc., occur in the upper part of 

 the dark clays at Black Ven, which represent in part the zone of A. raricostatus. 

 Some of these small Ammonites are cut and mounted for brooches. The zones 

 of A. armatus, A. Janiesoni, and A. ibex, although noted by Dr. Wright in the 

 Dorsetshire Cliffs, are not distinctly defined, but they may be generally 

 represented in the Belemnite Beds.' Saurian remains are met with at various 

 horizons at Black Ven, and in the limestones of Church Cliffs, etc. ; but good 

 specimens of these of course can only be obtained by the workmen engaged in 

 removing the stone, or by extensive excavations in the clays. Landslips occa- 

 sionally reveal specimens, but some of our finest examples have been obtained 

 piece by piece, by Mr. Samuel Clark, Mr. Robert Hunter, and others, who have 

 carefully watched the cliffs, and then devoted much labour to developing the 

 fossils from the limestone or cement-stone nodules in which they occur. 



Many fossil Fishes have been obtained from the Lower Lias at Lyme Regis, and 

 a number of genera have been founded, though Sir Philip Egerton has remarked 

 that many are represented each by a single type-specimen.^ 



In 1829, Dr. Buckland drew attention to the discovery of Coprolites in the 

 Lias at Lyme Regis. (See p. 104.) These had been called " Bezoar stones, 

 from their external resemblance to the concretions in the gall-bladder of the 

 Bezoar Goat, once so celebrated in medicine." They occur in the Lias shale and 

 stone, and may be picked up on the beach. Occasionally they form the nuclei of 

 small septaria. In size they vary from two to four inches in length, and from one 

 to two inches in diameter. Dr. Buckland attributed them to Fishes and Saurians.' 

 They frequently contain the beaks of Cuttle-fishes, besides Fish-scales, etc. 



Above the dark clays of Black Ven, which rise to a height of about 180 feet, 

 there is "a mass of marl, forming a cliff or wall, the dull-grey tint of which 

 strikingly distinguishes it from the darker strata below." This marl, which is 

 eighty or ninety feet thick, has been termed the Belemnite Beds by Mr. Day, who 

 regarded the division as the commencement of the Middle Lias, although 

 according to the grouping now adopted it must be included with the Lower Lias.* 

 Thin bands of limestone yielding A. raricostatus separate the dark clays below 

 from the Belemnite Beds above. Excepting Belemnites, these latter beds do not 

 yield many fossils, but they are capped by a thin bed of pale-grey limestone, 

 known as the Belemnite-stone, which yields Amiuonitcs HenLyi, etc., as well as 



^ Lias Ammonites (Pal. Soc. ), pp. 83, etc. 



* G. Mag. 1876, p. 441. 

 3 T. G. S. (2), iii. 223. 



* Q. J. xix. 280. 



