44 THE LIAS AMMONITES. 



of the Family Arietes are in general found together in great numbers ; whole strata are 

 sometimes composed of them, and they often grow to a very large size, from one to two 

 feet in diameter. They are exclusively and only special to the Lias formation, and 

 particularly in the lower beds thereof, where many different species are found. It is 

 still remarkable that this group stands wholly isolated from all the others," and is well 

 represented by Arietites Bucklandi, Conybeari, rotiformis, stellaris, semicostatus. In 

 North Germany the Arietenschichten are well developed, and very rich in organic 

 remains, as at Orsleben and near Harzburg, where the Bisulcatus-beds are worked for 

 ironstone. At Solenhai, near Liebenburg, and Falkenhagen, near Rischenau, the hydraulic 

 limestone marls are found with Arietites bisulcatus and Gryphaa arcuata'm great numbers. 

 In South Germany, in Wurttemberg, the Bucklandi-beds are developed near Stuttgart, 

 where they repose on the Angulatum-beds, which are worked at Vaihingen for hydraulic 

 limestone ; in these Pflastersteine are found large specimens of A. angulatum. For one of 

 these fossils, thirteen inches in diameter, I am indebted to my friend Professor Fraas. 

 The twenty feet of Angulaten-Schichten are overlain by a thin seam of yellow clay, on 

 which rests hard, dark-coloured limestone containing Arietites Bucklandi, Conybeari, 

 bisulcatus, obliquicostatus, Gryphaa arcuata, and numerous other Mollusca, so that the rock 

 is completely composed, as in several specimens before me, of shelly organic remains. The 

 Bucklandi-beds are only about three feet thick, but very fossiliferous, and the Museums 

 of Stuttgart and Tubingen contain extensive suites of fossils from these beds. In 

 Baden the Lower Lias is found at Malsch and Oestringen, in the Langenbriick Jura, 

 where the Planorbis-beds are overlain by the thick, hard, blue limestone of the Bucklandi- 

 beds, the Angulatum series being here almost absent. Arietites Bucklandi, A. spiratis- 

 simus, A. Turneri, Gryphaa arcuata, Lima Hermanni, L. yiyanlea, L. punctata, Pecten 

 tcxtorius, Pentacrinus tuberculatus, Mill., and Spirifer tumidus, are the leading fossils here. 



In the Breisgau Jura the Lower Lias is represented by the Bucklandi-beds, where 

 the same species are found as at Malsch. 



In the Swabian Jura at Kiissaburg the black bituminous limestone charged with 

 pyrites are overlain by bluish-grey thick limestone, extremely rich in organic remains. 

 Aeyoceras angulatum, Arietites Bucklandi, Conybeari, Sauzeanus, Turneri, Kridion, 

 raricostatus, Nautilus striatus, Pleurotomaria similis, Cardinia concinna, C crassiuscula, 

 Lima gigantea, L. Hermanni, Gryphcea arcuata, Pecten textorius, Spiriferina Walcotii, 

 Pentacrinus tuberculatus, Mill., are the fossils in these beds. 



F. Ritter von Hauer, in his classical monograph " Ueber die Cephalopoden aus dem 

 Lias der nordostlichen Alpen/' 1 has given beautiful figures and most accurate descriptions 

 of some of the most characteristic species of Ammonites from the Bucklandi-beds of the 

 Eastern Alps, where these shells lie in a red-coloured limestone; we here find Ar. 

 rotiformis, A. Conybeari, A. bisulcatus, A. spiratissimus, and A. tardicrescens, var. of 

 Conybeari, A. Kridion, A. stellaris, A. liassicus, A. hungaricus, A. Nodotianus, A. 

 multicostatus. All of these are well recognised forms of Bucklandi-zone. 

 1 Denk. Kaiser, 'Akademie der Wissenschaft,' Wien, 1856. 



