DAVIDSON SCOTTISH CARBONIFEROUS BEACHIOPODA. 



265 



For mucli of th.e infoi-mation relative to tlie localities in the last nine counties 

 I am indebted to Mr. Geikie, Mr. Page, Mr. Tate, Prof. Eamsay, Mr. Fraser, the 

 late Dr. Fleming, and H. Miller ; as well as to Sir R. Murckison and Mr. Salter, 

 Avho have kindly allowed me access to the hsts and specimens assembled during 

 the Geological Smwey of Scotland, I wish hkewise to express my thanks to 

 Profs, de Koninck and Phillips, Mr. Hancock, and to Dr. Gratiolet, of Paris, for 

 some of the information I have been able to communicate ; and to Mr. Mackie 

 for the care and trouble he has bestowed upon the pubhcation of this memoir. 



EXPLANATION OF THE PLATES. 



Plate XII. in Vol. 11. of the " Geologist." 



Fig. 1. Terehratula hastata, Sow. Nellfield, Lanarkshire. 



2, ■ . From Ayrshire ; in the collection of Mr. Young. 



This specimen shows remains of colour marking. 

 3 — L sacculus, Martia. From West Lothian and collection of 



Dr. Fleming. 



5. vesicularis, de Koninck. From West Lothian and collection 



of Dr. Fleming. 



6. Athyris ambigaa, Sow. Hallerhirst, Awshu'e. Collection of Mr. Arm- 



strong. 



7. . From Carluke, Lanai'kshire. 



8. . Interior of the Ventral Valve. A, adductor or oc- 



clusor ; R, divaricator muscular imj)ressions ; T, teeth j D, dental, or 

 rostral plates. 



9. . Interior of the Dorsal Valve. A A, quadruple im- 

 pressions of the occlusor muscle ; M, dental sockets ; N, hinge-plate ; 

 O, poiut from which the spirals (here omitted) were developed. 8 

 and 9 are from Capel Eig, East Kilbride, and collection of Mr. Arm- 

 strong. 



10 — 11. • plano-sulcata, Phillips. From Lanarksliire. In fig. 10 a 



portion of the lameUiform expansions are represented. 



12. Roijssii, L'Eveille. From Coalburn, near Lesmahago. A portion 



only of the pectmated fringes are represented. 



13. Retzia radialis, Philhps, var. From Brockley, near Lesmahago. Since 



this specimen was figured, several others have been found in the 

 same locahty, as well as at Gare. 



14. Sjjirifera duplicicosta, PhiUips. From Balgrochan Glen, Campsie, Stir- 



lingshhe. 



15. . From West Broadstone, Beith ; collection of 



Mr. J. Thompson. 



16. trigonalis, Martin. Brockley, near Lesmahago ; collection of 



Dr. Slimon. 



17. . From Cousland Burn, near Dalkeith. 



18. . Campsie ; collection of Mr. Young. 



19. lisulcata, Sow. Craigenglen, Campsie ; collection of Mr. 



Young. 



20. . West Broadstone, Beith ; collection of Mr. J. 



Thomson. 



21. . Ventral Valve, showing the imbricated surface; 



from Barrhead ; collection of Mr. A. Cowan. 



22. ■• West Broadstone ; collection of Mr. Armstrong. 



23. . A coarse-ribbed variety ; in the Museum of Prac- 

 tical Geology. 



VOL, III. 2 L 



