516 



FOSSILS OF THE MOUNTAIN LIMESTONE. [Ch. XX 7. 



ous forms, viz., the cup and star corals, belong, as before^ mentioned 

 (p. 515), to a distinct order, although they are often so like in out- 

 ward form as to have been referred in many cases to living reef-build- 

 ing genera. Hence we must not too confidently draw conclusions 

 from the modern to the palaeozoic polyps, respecting climate and the 

 temperature of the waters of the primeval seas, inasmuch as the two 

 groups of zoophytes are constructed on essentially different types. 

 When the great number of the palaeozoic and neozoic species is taken 

 into account, it is truly wonderful to find how constant the rule above 



Fig. 565. 



Fiff. 



Litlwstroiion basaltiforme, Phil. sp. {IA- 

 thostrotion striatum, Fleming; Astrcea 

 tasaltiformis, Conyb. and Phill.) Ken- 

 dall; Ireland; Eussia; Iowa, and west- 

 ward of the Mississippi, United States. 

 (D. D. Owen.) 



Lonsdaleia Jloriformis (Martin, sp.), M. 



Edwards. {Lithostrotion Jloriforme, 



Fleming. Strorribodes.) 

 a. Young specimen, with buds on the 



disk. 

 &.. Part of a full-grown compound mass, 



Bristol, &c. ; Eussia. 



explained holds good; only one exception having as yet occurred 

 of a quadripartite coral in a neozoic formation (the cretaceous), and 

 one only of the sextuple class (a Fungia?) in palseozoic (Silurian) 

 rocks. 



From a great number of lamelliferous corals met with in the Moun- 

 tain Limestone, two species have been selected, as having a very wide 

 range, extending from the eastern borders of Russia to the British 

 - Isles, and being found almost everywhere in each country. 



These fossils, together with numerous species of Zaphrentis, Am- 

 plexus, Cyathophyllum, Clisiophyllum, Syringopora, and Michelinea* 

 form a group widely different from any that preceded or followed 

 them. 



Of the Bryozoa, the prevailing forms are Fenestella and Polypora, 

 and these often form considerable beds. Their net-like fronds are 

 easily recognized. 



Crinoidea are also numerous in the Mountain Limestone. (See figs. 

 567, 568.) 



* For figures of these corals, see Pakeontographical Society's Monographs, 1852. 



