88 OUR COMMON BRITISH FOSSILS. 



one of the finest Carboniferous coral reefs in Great 

 Britain. There are many species of Lonsdalia, of 

 which rugosa and Jloriformis are perhaps the most 

 beautiful as well as the most abundant. Both show 

 structure in the clearest manner, and thin sections of 

 them, either transverse or horizontal, form exquisite 

 low-power objects for the microscope. The follow- 



Fi^. 6^.— Transverse secujii of Lonadalia rugosa. 



ing are among the British localities where different 

 species of Lonsdalia may be obtained : — Ecclefechan, 

 (Dumfriesshire), Boghead, Lesmahago, Clifton (near 

 Bristol), almost every part of Derbyshire where the 

 Carboniferous limestone crops up (but particularly 

 near Castleton), and in the Welsh localities above 

 mentioned. At Hafod and Boghead this fossil coral 

 is found in very large masses, in a capital state of 

 preservation. 



Lithostrotion (Figs. 42, etc.) is a widely diffused 



