134 DEVONIAN. 



The numerous remains of Corals render the rock, when polished, 

 very beautiful : it is termed Madrepore Marble. These Corals 

 belong to the species Hdiolitcs porosa, Favositts polymorpha, var. 

 cervicornis (Buck's Horn Marble, or Feather Stone), Cyathophylliim 

 ca:spitosu77i, Acervttlaria {Astriea) pentagona, Alveolites stiborbicularis, 

 Smithia i^Arachnophyllujii) Hennahi (Barton Star), Zaphrentis, etc. 

 The Feather Stone is found at Bradley Woods, Newton Abbot. 

 Corals are so rich in places as to give to the Devonshire marbles 

 much the appearance of Coral-reefs. ^ 



Among the Mollusca, Orthoceras undidatum, Cyrtoccras nodosum, 

 Clyinenia lezvigata, Gonia/ites excavaius, Loxonema, Euoniphalus, 

 Miirchisonia spinosa, Megalodoti ciicullatiis, Rhyjichojiella cuboides, 

 R. plcurodon, Spirifera disju7icta, Stringocephaliis Biirtini, Strepio- 

 rhynchus umhracuhim, Uncites gryphiis, etc., are found. The Hydro- 

 corallines include Stromafopora coticentrica, S. polymorpha, and .4 »;/>/?/- 

 pora ramosa ; a Sponge, Receptacidites, is also met with. The Crinoids, 

 Actinocrinus, Cyathocrinus, Platycrinus, and Cupressocrhms crassus, 

 likewise occur. The Great Devon Limestone is sometimes termed 

 the Stringocephalus Limestone, from the occurrence of S. Burtini; 

 good specimens of this Brachiopod are not readily to be obtained, 

 although crushed specimens are to be seen in great profusion at 

 Westhill, south of Chircombe Bridge. 



Trilobites are met with in the limestones, and in the underlying 

 slates, as Phacops latifrons, P. {^T7-i7nerocephalus) IcEvis, B/'07iteus 

 flabeUifi7', etc. These fossils are not common in the limestone, but 

 P. lavis has been met with in some abundance in the volcanic ash 

 at Knowle's Hill, Newton Abbot. The Starfish Helia7tth aster 

 filicifo7-77iis was discovered by Mr. Champernowne in a gritty bed 

 in the slates at Harbertonford, near Totnes. While Corals and 

 Encrinites help to form a large portion of the Devonian Limestone, 

 no Foraminifera have been recorded from it." 



The age of the Petherwin {Clyme7ita) limestone, south-west of 

 Launceston in Cornwall, has been matter of much dispute. 

 Clyt/icjiia has been obtained at the Landlake Quarry, also Go7iiatites, 

 Spu'ifc/-a Ver7ieuili, S. disjiaicta, 07-this striatula, Producta siibacideata, 

 Euo77iphahts se7pens, and the Trilobite Portlockia. Attention was first 

 directed to the fossils of this limestone by Mr. S. R. Pattison. 



Dr. Ferdinand Roemer regards the limestone as belonging to 

 the Clymenia stage of the Upper Devonian;^ but according to the 

 grouping now adopted, it must be placed with the Middle Devonian. 



In a limestone quarry at Lower Dunscombe, near Chudleigh, 

 Go/iiatites i7itumescc7is and G. multilobatiis were discovered by Mr. 

 J. E. Lee in the upper beds, which consist of thin red limestones. 

 The former species sometimes attained a diameter of nine inches. 

 Ca/'diola retrostriata, Ort/wceras, Phacops C7yptophthal/7ius and Coccosttus 



1 G. Mag. 1864, p. 42 ; W. Pengelly, Trans. Plymouth Inst. 1863, p. 17. 



"^ See Dr. H. C. Sorby, Address to Geol. Soc. 1879. 



3 G. Mag. 18S0, p. 147. See S. R. Pattison, Rep. R. G. S. Cornwall, 

 1S50, p. 132, and Proc. Geol. Assoc, ii. 279 ; Phillips, Palaeozoic Fossils of 

 Cornwall, etc., p. 195 ; and Sharpe, Q. J. iii. 77. 



