BUDLEIGH-SALTERTON PEBBLE-BED. 347 



C6tes-du-Nord, and the Finistere; and in another paper, "Congres du Havre," 1877, 

 they add that in the Departement of the Manche the Devonian presents the great 

 divisions recognised in Brittany, viz.: 



Grauwacke with Pleurodictyum problematicum. 

 Calcaire a Athyris undata (Nehou, Beaubigny). 

 Gres a Orthis Monnieri. 



In the 'Bulletin de la Soc. Geol. de France," 3rd ser., vol. iv, p. 615, 1876, M. de 

 Tromelin states that the Devonian series in the Departement of llle-et-Vilaine may be 

 divided in the following manner : 



■3. Schistes de Montigne (Mayenne). 



Schistes et Grauwackes de la Lezaie, de la Coudraie, &c, a Pleurodictyum 

 problematicum. 

 . Calcaires a Athyris undata de Gahard, d'Ize, de la Baconniere, &c, frequemment 

 mele de Schistes. 

 1. Gres a Orthis Monnieri de la Bodinaie pres Pierrie (Loire-Inferieure), de Gahard, 



de Saint Aubin d'Aubigne, et Gres homologues. 

 Orthis Monnieri is not a very common species in the yellow-sandstone and 

 quartzite pebbles at Budleigh-Salterton. Mr. Vicary has found it associated with Spirif. 

 Verneuilii in the same pebbles. In the same rocks, along with it, we also find Spirif erina 

 octoplicata and Rhynchonella elliptica. 



Orthis Monnieri is mentioned by M. Bonissent as occurring in the Devonian of the 

 De*partement de la Manche in his " Essai Geologique sur le Departement de la Manche ; 

 Terrain Devonien;" 'Memoires de la Soc. Imperiale des Sciences Naturelles de Cherbourg,' 

 1863. 



19, Orthis hipparionyx? Vanuxem. B. S. Sup., PI. XXXIX, fig. 1. 



A fragment of the internal cast of a large species of Orthis, somewhat resembling 

 Orthis hipparionyx, occurs in a Budleigh-Salterton pebble in the Museum of Practical 

 Geology. It is not sufficiently complete to warrant a certain specific identification. In 

 shape it is semicircular, and slightly longer than wide, hinge-line shorter than the breadth 

 of the shell, area narrow. In the cast the muscular area is large, pear-shaped, and 

 divided longitudinally by a small ridge. 



Specimens of Orthis hipparionyx resembling it occurs in the Oriskany Sandstone 

 (Hall, ' Pal. New York,' vol. iii, pi. lxxxix, fig. 4). Well characterised specimens of 

 Vanuxem's species are also found in the Devonian Sandstone at Looe, Cornwall ; also in 

 the " Gres Devonien " or etage a Orthis Monnieri, at Gahard, in Brittany. It bears, 

 likewise, a resemblance to a specimen of 0. hipparionyx, figured by Schnur in his work 

 on the ' Eifel. Brachiopoden,' pi. xl, fig. 1 a. 



