50 



THE LIAS AMMONITES. 





Section from Broad Ledge 



to Cornstone Ledge, near Charmouth. 



No. 



1 



2 

 3 



4 

 5 



6 



7 



8 



9 



10 

 11 

 12 

 13 

 14 

 15 



IC 

 17 



18 



19 



20 



LiTHOLOGY. 



Thick- 

 ness. 



Organic Remains. 



Dark-grey limestone. " Cornstone 

 Ledge." 



Dark-bluish marls 



Dark-greyish limestone 



ft, 



20 

 



3 

 9 



4 



2 

 4 

 2 



2 



5 



2 



30 



4 

 3 



in. 





 10 





 





 

 

 











6 









 



Fishes in fine preservation as Pachycormus, ^ch- 

 modus, Dapedius, Acrodus, Hybodus, &c. 



Ichthyosaurus platyodon, Conyb., and /. inler- 

 medius, Conyb. Aegoceras Birchii, Sow, 



Nautilus striatus. Sow., Arietites Brookii, Sow,, 



and Arietites stellaris. Sow, (very large). 

 Dapedius punctatus, Dapedius Culei, Ag. 



Dapedius granulatus. jEchmodus pustulatus, Ag, 

 Scelidosaurvs Harrisonii, Owen. Inoceramus 

 pinnceformis. Lepidotiis fimbriatus, Agass. 



Extracrinus Briareus, Mill. 

 Arietites stellaris. Ar. semicostatus. 



Chondrosteus acipenseroides, Agass. 

 Chondrosteus, Lepidotus, Conodus ferox, Ag, 



Aegoceras planicosta, Sow., and Arietites Smithii, 



Ar. obtiisus. Sow., Lepidotus rugosus, Ag, 

 Saurian skeletons. Fishes. 

 Arietites obtusus. Sow., and Aegoceras Birchii, 



Sow. 

 The nodules contain Saurian remains. Penta- 



crinus, sp., Ichthyosaurus platyodon. 

 This bed overlies the Lima-series east of Lyme- 



Regis, 

 Aegoceras Birchii, Sow, 



Dark clays. 



Dark limestone, with nodules and 

 septaria 



Dark shale. 



Dark limestone, " Upper Cement- 

 bed " 



Dark shales, containing mudstone no- 

 dules at the base 



Thin band of limestone. The " Penta- 

 crinite bed " 



Dark shales. "\ 



Dark limestone. C«Fireledffe" 

 Dark shale. C ^i^e-ledge. 



Dark limestone. ) 



Dark shale. 



Dark limestone " Split-ledge." 



Dark shales 



Greyish limestone crystallised, forming 

 the " Tortoise-ammonites " 



Dark marls, with nodular masses. The 

 lower Cement-beds &c. &c 



Dark indurated shale and limestone, 

 "Broad Ledge," 



The Nut rocks 



Zone of Arietites Turneri. 

 Thick Limestone : Broad Ledge. | Saurian Skeleton. 



The 05fusus-zone attains a thickness of from 80 to 100 feet ; its actual measurement 

 is a matter of difficulty, the marls having covered up the bands of limestone. 



In the lower marls are many compressed specimens of Aegoceras Birchii, which fall to 

 pieces when removed from the matrix. Higher up (No. 17) this Ammonite is found in 

 fine preservation, with Arietites obtusus. Here the shells are replaced, and their chambers 

 filled, with crystallised carbonate of lime. These beautiful specimens are the " Tortoise- 

 ammonites " of local collectors. About 40 or 50 feet above the latter an irregular band 

 of limestone (5) is seen projecting from the cliff, containing nodules with very large 

 specimens of Arietites obtusus, Sow,, Arietites stellaris. Sow., and Arietites Brookii, Sow. 

 Most of the nodules have a septarian structure, the veins of spar intersecting and 

 distorting the fossil contents of the bed. 



Below the ammonitiferous nodules (5 of the section) other bands of clay and marl 

 (6 to 14) succeed. In one of these (9) are thin, wide-spread layers of Crinoidal lime- 

 stone, on the surface of which magnificent specimens of Extracrinus Briareus, Mill., are 



